Linear actuation device for brake caliper and brake caliper having such device

Abstract

A linear actuation device (1) for a brake caliper (2) adapted to bias at least one brake pad (3) so as to abut it against a braking surface (4) of a brake disc (5) wherein the device comprises a motor (6) comprising a rotary drive shaft (7) and a stator (8), a harmonic drive (10) and a rotary-linear motion conversion device (12); the invention relates to a harmonic drive (10) comprising: a rotary wave generator (9), referred to as a wave generator, of a strain wave drive of said harmonic drive (10), said rotary wave generator (9) being at least partially made in one piece with said rotary drive shaft (7); a harmonic reducer (11) of the harmonic drive (10); the harmonic reducer (11) is elastically deformed and rotated by the rotating wave generator (9); rotary-linear motion conversion means adapted to convert a rotary motion into a linear motion and to bias said at least one brake pad (3) in an axial direction (A-A) so as to abut said at least one brake pad against said braking surface (4); the rotary-linear motion conversion device (12) is rotatably connected to the harmonic reducer (11).

Description

Technical Field

[0001] The present invention relates to the technical field of actuating devices of a brake caliper of a disc brake suitable for decelerating or parking a vehicle. The present invention also relates to a brake caliper comprising at least one actuating device of the brake caliper. The present invention also relates to a disc brake comprising a brake caliper comprising at least one actuating device of the brake caliper.

[0002] In particular, the present invention relates to the technical field of electromechanical brake devices. Background Art

[0003] In a disc brake, a brake caliper is usually arranged to straddle the peripheral edge of a brake disc, the brake disc being adapted to rotate about an axis of rotation (AA) defining an axial direction (XX). In the disc brake, a radial direction (RR) substantially orthogonal to the axial direction (XX) and a tangential direction (CC) or circumferential direction (CC) is also defined, the tangential direction (CC) or circumferential direction (CC) being orthogonal to both the axial direction (XX) and the radial direction (RR).

[0004] The brake caliper is constrained to a support structure which remains stationary relative to the wheel, such as a steering shaft of a vehicle suspension, or a wheel hub, or a fork. The brake caliper generally comprises a caliper body having two elongated parts arranged to face opposite braking surfaces of a brake disc and at least one bridge connecting the two elongated parts to each other. The caliper, being actuated, presses the pads against the brake band, and the braking action is produced by the friction between the pads and the brake band of the brake disc.

[0005] Current brake systems, especially electric brake systems, suffer from the disadvantage of being highly complex in structure and layout due to the need to apply electromechanical actuation systems to the brake systems. This complexity is also evident from the number of components involved and hence from their integration in the brake caliper.

[0006] In particular, there is a strong need to modularize the electric actuation function of the brake caliper by simplifying the transmission and torque multiplication functions and maximizing the integration of the components involved in generating the brake pressure, creating a single subassembly compatible with various brake systems.

[0007] The combined technical use included in the context of the functions required for electromechanical actuation of a brake system enhances the object of the invention by making full use of some characteristics that are lacking in the solutions currently used on the market and opens up new development prospects in the field of electrically actuated brake systems.

[0008] In the related art, various solutions for transmission devices (reducers) for electrically actuated calipers can be found. For example:

[0009] - Gear cascade transmission;

[0010] - a transmission with planetary gears;

[0011] - Hybrid transmission with gear cascade and planetary gear.

[0012] Such solutions are known, for example, from US10421445B2, US6367593B1, US6412610B1, WO2020101444A1, EP1321691B1.

[0013] Document US2020156612A1 of Toyota Motor CO LTD describes an actuator for a brake caliper. The actuator includes: a housing; an electric motor having a rotating hollow drive shaft; a rotating shaft arranged inside the drive shaft and coaxial with the drive shaft; a piston having a rear end arranged inside the drive shaft and a front end engaged with a brake pad; a speed reduction mechanism that reduces the rotation transmitted by the drive shaft and transmits the rotation to the rotating shaft; and a motion conversion mechanism that converts the rotational motion of the rotating shaft into the forward / backward motion of the piston. The drive shaft is rotatably supported by the housing at the outer peripheral surface of the drive shaft, and the rotating shaft is rotatably supported by the inner peripheral surface of the drive shaft at the outer peripheral surface of the rotating shaft by means of a ball bearing and rotatably supported by the housing at the rear end of the rotating shaft by means of a thrust bearing.

[0014] Document CN1836116A of PBR Australia PTY LTD describes an actuator comprising: an electric motor in which a rotor defines a bearing surface having a non-circular profile; and a radially flexible annular sleeve (24) defining a facing bearing surface. The flexible sleeve presents a non-circular shape complementary to the profile of the resting surface. The flexible sleeve is restrained from rotation and is meshingly engaged with a circular transmission ring in at least two contact areas equidistant from each other by means of teeth. The transmission ring is rotationally engaged with the screw and threaded sleeve assembly so that rotation of the transmission ring actuates the screw assembly and causes the exit portion of the screw to extend or retract. The actuator is actuatable so that rotation of the rotor causes the flexible sleeve to bend radially in each of the contact areas to produce a rolling wave, which causes rotation of the contact areas and the transmission ring, and the transmission ring rotates at a rotational speed that is lower than the rotational speed of the rotor.

[0015] Document EP3434925A1 shows a brake caliper, which includes a main body unit, a brake unit and an actuating unit. The main body unit includes a first side seat and a second side seat connected to each other. The brake unit includes a first group of push arms and a second group of push arms respectively mounted on the first side seat and the second side seat. The actuating unit moves at least a portion of the first push arm assembly. The first push arm assembly includes a self-aligning module, which includes at least one self-aligning joint to allow misalignment between the first side seat and a portion of the first push arm assembly without causing interference between the first push arm assembly and the first side seat.

[0016] Document CN204592094U of Jilin University shows an actuator for an electrically actuated mechanical brake of a vehicle, which includes a housing body of a motor with a harmonic reducer. The power from the motor passes through a drive shaft and a harmonic reducer, and the teeth of the flexible gear of the toothed wheel are connected to a circulating ball screw coupled to a nut to feed the friction pad against the brake disc. The motor is screwed to the reducer, which in turn is screwed to a support of the nut, which keeps the screw axially restricted.

[0017] However, these known solutions have the following problems:

[0018] - Large axial volume, making it difficult to install on the vehicle;

[0019] - Large radial volume, making it difficult to integrate with the caliper body and the entire housing in the wheel well;

[0020] - Large number of components;

[0021] - Complexity of product assembly (electromechanical calipers);

[0022] - Complexity of product design;

[0023] - Large mechanical play in the mechanical transmission (gear train and planetary gears lead to an increased reduction in the response time of the brake caliper and the brake system);

[0024] - An additional actuation auxiliary electromechanical unit is required to achieve the stationary function;

[0025] - Uncontrolled reversibility in the event of a fault.

[0026] One proposed solution for making electromechanical actuators compact is through the use of harmonic gearing (strain wave) technology, also known as Harmonic Drive TM Brand name.

[0027] For example, according to document US6664711B2, it is known to make a harmonic transmission in which a motor inside the transmission magnetically excites a central flexible ring which deforms so as to form a rotating ellipse capable of meshing on an outer ring having a higher number of teeth than said flexible ring. Although this known solution is very compact, it is very complex to manage both from a construction and control point of view, has limited power due to the small size of the motor, and is difficult to cool.

[0028] From document EP1877677B1 is known the application of a solution similar to that described in US6664711B2 for generating the rotary motion of a worm keyed into a nut serving as a pusher for the pads in a brake caliper. All the disadvantages present in the solution of US6664711B2 are therefore also present in the applied solution of EP1877677B1.

[0029] From document CN104806669A an electrically actuated brake caliper solution is known, in which a motor is coupled to and moves a harmonic drive which rotates a worm which moves a nut - acting as an abutment piston for a brake pad - against a brake disc.

[0030] Although this known solution simplifies the transmission, it is obviously very bulky due to the use of components arranged in series with one another.

[0031] From document US2009057074A1 an electrically actuated caliper solution is known, in which a motor is connected to and moves a harmonic drive which rotates a plate which translates a facing plate via a cam, thereby intervening on the balls to reduce friction (also called a ball-on-ramp drive).

[0032] Therefore, this known solution does not reduce the construction complexity compared to the CN104806669A solution and strongly maintains the need to incorporate components to reduce the complexity and bulk of the solution while maintaining sufficient movement reduction and efficiency. Summary of the invention

[0033] The object of the present invention is to provide a linear actuating device capable of resolving the drawbacks of the related art and having in particular reduced complexity and limited volume.

[0034] This object and advantages and others are achieved by a device according to claim 1 , a brake calliper according to claim 17 , and a disc brake according to claim 18 .

[0035] Advantageous embodiments are the subject matter of the dependent claims.

[0036] The analysis of the solution has shown that the proposed solution allows to obtain a solution with better performance compared to the solutions of the related art.

[0037] Specifically, the advantages provided by the present invention can be summarized as follows:

[0038] - Weight reduction, which is a particularly important factor for brake calipers, which are unsprung masses;

[0039] - Reduced number of parts;

[0040] - Reduced volume size;

[0041] - Simplified product layout;

[0042] - the integration between the device and the brake caliper body is simplified, thus allowing a modular design and in particular avoiding the need to redesign the caliper and transmission assembly for each new application;

[0043] - Due to the possibility of having a higher reduction ratio, the parking brake function can be realized without incorporating the actuation of an auxiliary electromechanical unit, as mentioned under the given transmission design conditions;

[0044] - A reduction in the response time of the brake caliper is achieved due to the simplification and arrangement of the combined harmonic drive;

[0045] - Improved mechanical reliability by reducing the number of parts;

[0046] - Increased quietness of transmission components;

[0047] - Achieves controlled reversibility in the event of an electrical fault under given transmission design conditions;

[0048] -Simplification of industrialization and monitoring of safety features.

[0049] By the scheme described below, the following subunits are provided in the scheme, for example:

[0050] -BLDC (brushless DC) motor;

[0051] - wave generators obtained using rolling bearings, for example ball bearings;

[0052] - a flexible key obtained by means of a deformable cup-shaped member;

[0053] - a fixed ring gear obtained by means of a static ring;

[0054] - a rotary-to-linear motion conversion device which allows the conversion of torque into force (for example, a recirculating screw or a device with balls on ramps);

[0055] - providing axial and radial bearings to release the action on the cover housing and allow rotation without translation of some components;

[0056] - a pusher (screw or plate) for controlling a pusher plate arranged on at least one pad and a non-axial force disconnection joint;

[0057] -Anti-rotation device;

[0058] - seals;

[0059] -Force sensor.

[0060] One of the novel components is the strain wave gear transmission (known under the name Harmonic Rather, it is known) and is highly integrated with a rotary-linear motion conversion device.

[0061] For example, making the drive shaft as a hollow steel cylinder allows to house a series of permanent magnets while obtaining a non-circular track capable of having a wave generator that allows to generate strain wave gearing type transmission waves.

[0062] The use of a hollow rotary shaft motor permits the incorporation therein of a device for converting rotary motion into linear motion (when in a retracted state with new, unworn brake pads), for example, a recirculating ball screw, or a facing plate device known as a ball-on-ramp device, and axial and radial bearings.

[0063] For example, a flexible cup or bell (also called a flexible key) made of harmonic steel is deformed by the push of balls rolling on an elliptical track of a wave generator (built into the rotor), thereby transmitting torque to a motion conversion device (for example, a circulating ball or a screw with balls placed on a ramp) due to a forced connection.

[0064] Providing torque to the nut of the circulating screw allows positioning the devices required for wear recovery away from the pads, compared to the way the related art is used. Thus, this part of the system will be housed inside the hollow drive shaft, optimizing space utilization and making the solution compact.

[0065] For example, the use of balls placed on ramps allows making systems with motion conversion features, even of non-linear type, depending on the shape of the ramps, or tracks, or cams that generate the lift of the rolling elements.

[0066] For example, the force generated by the device acts on the pad through a push plate which is disconnected from the push device (screw or plate with balls resting on ramps) by a joint and a shoe to avoid that other forces than pure axial forces are transmitted to the mechanism.

[0067] For example, all components except the following are made of steel (harmonic steel, quenched and tempered steel, and plastically deformed steel):

[0068] - a holder for the support of the wave generator, the holder being made of aluminium or brass;

[0069] - Permanent magnets of the rotor, made of neodymium;

[0070] - an overmoulding of the magnet, the overmoulding being made of plastic;

[0071] - Axial thrust bearing cage, the cage is made of aluminum or brass;

[0072] - Rubber seals.

[0073] The invention allows the manufacture of an electromechanical caliper with a reduced number of components (about -50% in the present embodiment) and having the following advantages:

[0074] - the device is simply integrated into the caliper body, for example by screwing the cover housing to the edge of a seat provided in the caliper body, the system is assembled and mounted on the vehicle (the module itself is screwed, or welding, etc., may be performed);

[0075] - higher mechanical reliability, calculated as the product of the reliability of the chain of components forming the device;

[0076] - Modularity of installation by using the same actuation on different calipers for each application / customer and vehicle side (right / left).

[0077] The advantages provided by this system, which ensures the conversion of motor torque into linear force when applied to the brake device, are mainly reflected in:

[0078] - Weight reduction

[0079] The compactness of the solution obtained due to the high degree of integration of the components involved in obtaining the functionality of a conventional transmission allows reducing the weight component due to the transmission and offers the opportunity to reduce the mass component of the suspension required by the major car manufacturers.

[0080] - Fewer parts

[0081] The combination of rotor, hollow drive shaft and transmission allows the components involved in the electromechanical transmission applied to the wire control brake system to be reduced by almost 2 / 3; this simplification leads to a reduction in volume size with the same functionality and also improves mechanical reliability by reducing the number of components involved.

[0082] - Simplified layout

[0083] The proposed architecture creates a load path perpendicular to the pressure zone that the system should develop to apply braking torque to the vehicle. The low number of components involved provides the opportunity to reduce the load path and therefore reduce external causes of inefficiency.

[0084] -Simplified integration of foundation brake (caliper body)

[0085] This solution allows the development to be evaluated without regard to the external design of the brake caliper; this provides the opportunity to produce a modular design where the foundation brake only requires the mechanical interface of the actuator "module" to be developed, providing more freedom for aesthetic and performance development.

[0086] Furthermore, the opportunities that can be gained from a "modular" architecture such as the one proposed for electromechanical brake calipers derive from the greater industrial production flexibility inherent in the proposed solution. This therefore leads to simplified or low-impact changes to:

[0087] -Creation of caliper blanks;

[0088] - Mechanical work;

[0089] - Caliper assembly;

[0090] -Aesthetic treatment;

[0091] - Incorporation of actuation modules;

[0092] - Functional control;

[0093] - Reduced response time.

[0094] The lower number of components and simpler layout allow for greater design management of clearances (required for assemblability), thereby allowing for an increased ability to manage the electrically actuated mechanics and thus shorten actuation times.

[0095] - Quietness

[0096] The proposed simplification aimed at reducing the dynamic components involved in the motion conversion allows reducing creep and collision dynamics, which are the main causes of noise generation in mechanical transmissions.

[0097] Furthermore, the proposed solution with a special transmission reduction design allows the integration of a parking brake function without the need for additional components.

[0098] The characteristic of a harmonic reducer or harmonic drive device involves the poor reversibility of the system, which does not allow the spontaneous retraction of the reducer when the torque value at the reducer output is lower than a given torque value (reverse drive torque). This results in a mechanical locking system that can be used by the caliper to perform the vehicle parking function. This allows the parking torque and its correction to be managed by exploiting the function of the actuating motor, thus avoiding the incorporation of another mechanical / electromechanical locking device. This means: the solution can have two configurations depending on the required dimensioning:

[0099] - Parking brake function inherent in the transmission characteristics;

[0100] - Parking brake functionality not inherent in the solution, but in combination with additional devices / components.

[0101] - Simplification of industrialization and monitoring of safety features

[0102] Reducing the number of parts required for assembly and the number of machining operations and modifications to the caliper to achieve the braking function allows a reduction in the number of controls and key features to be monitored, thus simplifying parts management. This plays a role in the occurrence of production waste and production problems.

[0103] Key features include the retarder retraction torque, which can be used to eliminate the need for an additional parking brake.

[0104] However, by utilizing the high gear ratios that a strain wave gear type reducer can provide, the pitch of the rotary-to-linear motion converter track (the helix angle or profile of the cam on which the balls rest on the ramps) can be increased to promote reversibility at the expense of greater torque required at the output of the transmission.

[0105] Therefore, the size setting of the present invention can be performed in two ways:

[0106] 1) A reversible system that provides torque to the reducer only through an additional device;

[0107] 2) A system that is spontaneously reversible each time a biasing action of the elastic force stored in the caliper is applied.

[0108] In type 2 dimensioning, the screw portion of the torque-force converter (circulating or ball-on-ramp screw) must be selected so that: at a given force value dictated by the system requirements and the selected safety concept, the typical retraction torque of the reducer will always be less than the loosening torque of the torque-force converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Further features and advantages of the device, the disc brake and the method will become apparent from the following description of a preferred embodiment of the invention given by way of non-limiting example with reference to the accompanying drawings, in which:

[0110] - Figure 1 shows a wheel-side axonometric view of a disc brake according to the invention;

[0111] - Figure 2 Shows Figure 1 A radial view of a disc brake without a brake disc, facing the axis of rotation of the brake disc;

[0112] - Figure 3 Shows Figure 1 Axial view of the disc brake facing the wheel;

[0113] - Figure 4 Shows Figure 1 A cross-sectional view of a disc brake without a brake disc in an axial radial plane passing through the axis of rotation of the linear actuator;

[0114] - Figure 5 Shows Figure 1 An axonometric view of a separate part of a brake caliper of a disc brake without a brake disc, viewed towards the vehicle;

[0115] - Figure 6 Shows Figure 1 An axonometric view of a separate part of a brake caliper of a disc brake without a brake disc, viewed towards the wheel;

[0116] - Figure 7 shows a cross-sectional view of the linear actuator in an axial radial plane passing through the axis of rotation of the linear actuator, associated only with the push plate and the dust seal and in a retracted position;

[0117] - Figure 8 A cross-sectional view on an axial radial plane passing through the axis of rotation of the linear actuator device is shown, in association with the push plate and the dust seal only and in an extended position;

[0118] - Fig. 9 A partial cross-sectional view of a harmonic drive of a linear actuator in a radial circumferential plane is shown;

[0119] - Fig.10 shows a cross-sectional view on an axial radial plane passing through the axis of rotation of a linear actuation device according to the following variant: in this variant, the rotary-linear motion conversion device is of the ball-in-ramp type;

[0120] - Fig.11shows an axonometric view of a push side or push plate side of a linear actuating device according to a variant;

[0121] - Fig.12 Shows Fig.11 an axonometric view of a linear actuator in the embodiment of the present invention with its components separated;

[0122] - Fig.13 shows a cross-sectional view on an axial radial plane passing through the axis of rotation of a linear actuation device according to a variant in which the cover housing supports all the components of the linear actuation device in a self-supporting manner by forming a cartridge that can be removably applied to the caliper body;

[0123] - Fig.14 Shows Fig.13 an axonometric cross-sectional view of the linear actuator in an axial radial plane passing through the rotation axis of the linear actuator;

[0124] - Figures 15 to 19 shows an axonometric or orthogonal view of a brake caliper provided with a linear actuation device according to the invention;

[0125] - Fig. 20 and Fig.21 Shows Figures 15 to 19 Axonometric view of the brake caliper with the components separated. DETAILED DESCRIPTION

[0126] In the following, when referring to the terms "radial" or "radial direction" and "axial" or "axial direction" and "circumferential" or "circumferential direction", unless expressly defined otherwise, reference will be made to the directions previously defined with reference to the brake disc and the axially symmetrical shape of the brake disc, the same directions also being used for the brake caliper, or the brake caliper body, or the actuating device, as if the brake caliper, or the brake caliper body, or the actuating device were mounted and placed in association with the brake disc.

[0127] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 is described below, which is adapted to bias at least one brake pad 3 against a braking surface 4 of a brake disc 5 .

[0128] The device comprises a motor 6. The motor 6 comprises a rotating drive shaft 7 and a stator 8.

[0129] The device also comprises a rotary wave generator 9, referred to as a wave generator, which interacts with a strain wave transmission of a harmonic transmission 10, referred to as a strain wave transmission.

[0130] The rotary wave generator 9 is made in one piece with the rotary drive shaft 7 .

[0131] The harmonic drive device 10 includes a harmonic reducer 11. The harmonic reducer 11 is elastically deformed and rotated by the rotary wave generator 9.

[0132] The device further comprises a rotational-linear motion conversion device 12 adapted to convert a rotational motion into a linear motion and to bias said at least one brake pad 3 along an axial direction AA so that said at least one brake pad 3 abuts against said braking surface 4 .

[0133] The rotation-linear motion conversion device 12 is rotatably connected to the harmonic reducer 11 .

[0134] According to an embodiment, said drive shaft 7 has a tubular body 13 forming a drive shaft interior chamber 14 .

[0135] The rotary-linear motion conversion device 12 is at least partially housed within the drive shaft interior chamber 14 .

[0136] According to an embodiment, the harmonic transmission device 10 is stacked on the rotation-linear motion conversion device 12 .

[0137] According to an embodiment, the rotary-linear motion conversion device 12 comprises a nut 281 meshing with a worm 29 which translates along the axial direction AA when the nut 281 rotates. The harmonic transmission device 10 is superimposed on the nut 281.

[0138] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 is described below, which is adapted to bias at least one brake pad 3 against a braking surface 4 of a brake disc 5 .

[0139] The device 1 comprises a motor 6. The motor 6 comprises a rotating drive shaft 7 and a stator 8.

[0140] The drive shaft 7 has a tubular body 13 forming a drive shaft interior chamber 14 .

[0141] The drive shaft 7 is directly and operatively connected to a harmonic drive 10 , also known as a strain wave drive.

[0142] The harmonic drive device 10 is directly and operatively connected to a rotary-to-linear motion conversion device 12, which is adapted to convert rotary motion into linear motion.

[0143] The rotational-linear motion conversion device 12 is adapted to bias the at least one brake pad 3 along the axial direction AA so that the at least one brake pad 3 bears against the braking surface 4 .

[0144] The rotary-linear motion conversion device 12 is at least partially housed within the drive shaft interior chamber 14 .

[0145] According to an embodiment, the device comprises a rotating wave generator 9, referred to as a wave generator.

[0146] The device further comprises a harmonic reducer 11 of the harmonic transmission device 10 .

[0147] The harmonic reducer 11 is elastically deformed and rotated by the rotary wave generator 9. The rotary wave generator 9 is at least partially made in one piece with the rotary drive shaft 7.

[0148] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 is described below, which is suitable for biasing at least one brake pad 3 against a braking surface 4 of a brake disc 5, and is also called a cylinder.

[0149] The device 1 comprises a motor 6 including a rotating drive shaft 7 and a stator 8 .

[0150] The drive shaft 7 is directly and operatively connected to a harmonic drive 10 known as a strain wave drive.

[0151] The harmonic drive device 10 is directly and operatively connected to a rotary-to-linear motion conversion device 12, which is adapted to convert rotary motion into linear motion.

[0152] The linear actuator 1 comprises a cover receiving portion 36 .

[0153] The cover receiving portion 36 receives the following items in a self-supporting manner:

[0154] The motor 6; and

[0155] The harmonic drive device 10; and

[0156] The rotation-linear motion conversion device 12,

[0157] The rotational-linear motion conversion device 12 is free to bias the at least one brake pad 3 along the axial direction AA so that the at least one brake pad 3 bears against the braking surface 4 .

[0158] According to an embodiment, the cover receiving portion 36 is fitted into a caliper body seat 39 provided in the caliper body 50 by completely fitting the cover receiving portion 36 from the outside of the caliper body 50. For example, the caliper body seat 39 includes an internal connection threaded portion 58 for a cylinder, and the cover receiving portion 36 includes an external connection counter-threading 59 for a cylinder of a linear actuator on the outside, and the cover receiving portion 36 is screwed through the threaded portions 58, 59.

[0159] According to an embodiment, said cover housing 36 is a single piece, ie in one piece.

[0160] According to an embodiment, the harmonic drive device 10 includes a harmonic reducer 11 , and the harmonic reducer 11 includes a flexible cup 22 and a static ring 26 .

[0161] The static ring 26 is keyed to and supported by the cover receptacle 36 .

[0162] According to an embodiment, said cover housing 36 comprises a removable fastener 48 for removably fixing the linear actuation device 1 to the caliper body seat 39 .

[0163] According to an embodiment, said cover housing portion 36 comprises a threaded portion 48 for removably fixing the linear actuating device 1 to a caliper body seat 39 having a seat corresponding threaded portion 49 .

[0164] According to an embodiment, said motor 6 is an electric motor.

[0165] According to an embodiment, the motor 6 is a brushless electric motor, for example known as BLDC.

[0166] According to an embodiment, the motor 6 is a brushless electric motor and the rotary drive shaft 7 comprises permanent magnets 15 .

[0167] According to an embodiment, the motor 6 is a brushless electric motor and the rotary drive shaft 7 comprises a permanent magnet 15 comprising plasmatone odymium.

[0168] The motor 6 is a brushless electric motor and the rotary drive shaft 7 comprises a permanent magnet 15 embedded in the body of the rotary drive shaft 7 .

[0169] According to an embodiment, said rotating wave generator 9 is an elliptical support 21 .

[0170] According to an embodiment, the rotary drive shaft 7 comprises at least one drive shaft bearing seat 17; the drive shaft bearing seat 17 is concentric with the rotation axis MM of the motor parallel to the axial direction AA.

[0171] The rotary drive shaft 7 is formed in an integral manner with an elliptical supporting rotary ring 18, and the elliptical supporting rotary ring 18 forms an elliptical rolling track.

[0172] Associated with said elliptical bearing rotating ring 18 are elliptical bearing rolling elements 19 and an outer elliptical bearing rotating ring 20 , forming an elliptical bearing 21 .

[0173] According to an embodiment, the harmonic drive device 10 includes a harmonic reducer 11 .

[0174] The harmonic reducer 11 includes a flexible cup-shaped member 22 and a static ring-shaped member 26 .

[0175] The flex cup 22 comprises a flexible portion 24 of the flex cup, referred to as a flex spline, to which the portion of the elliptical support 21 which elastically deforms the flex spline 24 is splined.

[0176] The flexible portion 24 of the flexible cup comprises cup teeth 25 on opposite sides.

[0177] The harmonic reducer 11 includes a ring-shaped static annular member 26 .

[0178] The static ring 26 comprises a ring toothing 27 .

[0179] In the case where the deformed flexible cup 22 has the maximum diameter, the cup teeth 25 mesh with the ring teeth 27 .

[0180] The cup-shaped member teeth 25 are less in number than the ring-shaped member teeth 27 so that: when the flexible portion 24 of the flexible cup-shaped member is deformed, the cup-shaped member teeth 25 engage with the ring-shaped member teeth 27 at at least two points, for example, the cup-shaped member teeth 25 engage with the ring-shaped member teeth 27 at opposite ends of the same engagement diameter portion.

[0181] The linear actuator 1 comprises a cover receiving portion 36 .

[0182] The static annular element 26 is fixedly keyed to the caliper body of the brake caliper 2. According to a different embodiment, the static annular element 26 is fixedly keyed to the cover housing 36.

[0183] According to an embodiment, the harmonic drive device 10 includes a harmonic reducer 11, and the harmonic reducer 11 includes a flexible cup 22 and a static ring 26 that mesh with each other at at least two points.

[0184] The flexible cup 22 comprises a cup connecting portion 28 to be keyed to the rotary-linear motion conversion device 12 .

[0185] According to an embodiment, the harmonic drive device 10 includes a harmonic reducer 11 .

[0186] 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, the flexible cup 22 and the static ring 26 mesh with each other at two teeth.

[0187] The flexible cup 22 comprises a cup connection portion 28 formed by a tubular sleeve.

[0188] The cup connection portion 28 formed by a tubular sleeve is keyed to a nut 281 .

[0189] The nut 281 is supported to rotate freely and is axially restricted to prevent the nut 281 from moving in the axial direction AA.

[0190] The nut 281 meshes with the worm 29 , which translates along the axial direction AA when the nut 281 rotates.

[0191] According to an embodiment, the flexible cup 22 comprises a cup connecting portion 28 .

[0192] The cup connecting portion 28 is connected to the rotary-linear motion conversion device 12 , and the cup connecting portion 28 is mainly arranged in the drive shaft inner chamber 14 .

[0193] The rotation-linear motion conversion device 12 includes a nut 281 that accommodates the worm 29 .

[0194] The worm 29 is engaged in the nut 281 and converts the rotational motion of the nut 281 into the linear motion of the worm 29 .

[0195] According to an embodiment, the rotation-linear motion conversion device 12 comprises a nut 281 which houses a recirculating ball worm 29 .

[0196] The worm 29 is engaged in the nut 281 and converts the rotational motion of the nut 281 into the linear motion of the worm 29 .

[0197] According to an embodiment, the rotary-linear motion conversion device 12 is substantially completely contained in the drive shaft internal chamber 14 when in the retracted position, for example, except for a push plate adapted to be arranged on the brake pad, which protrudes outward to interact with the brake pad, the rotary-linear motion conversion device 12 is substantially completely contained in the drive shaft internal chamber 14 when in the retracted position.

[0198] According to an embodiment, the flexible cup 22 comprises a cup connection portion 28 ; the cup connection portion 28 is connected to a first plate 30 .

[0199] According to an embodiment, said first plate 30 comprises a ramp-like track 31 extending circumferentially in a circumferential direction around said axial direction AA and extending gradually in the axial direction AA.

[0200] The first plate 30 is restrained in translation along the axial direction AA to prevent axial movement of the first plate 30 , and the first plate 30 is free to rotate about the axial direction AA.

[0201] The ramp-shaped track 31 accommodates a plate rolling element 32 , which is, for example, a ball or a roller.

[0202] The first plate 30 faces the second plate 33 .

[0203] The second plate 33 includes a second plate seat portion 34 accommodating the plate rolling element 32 , wherein the second plate seat portion 34 faces the ramp-shaped track 31 .

[0204] The first plate 30 or the second plate 33 is restricted in translation along the axial direction AA to avoid axial movement of the first plate 30 or the second plate 33 , and the first plate 30 or the second plate 33 is free to rotate around the axial direction AA.

[0205] The second plate 33 or the first plate 30 is restricted in rotation, and the second plate 33 or the first plate 30 is free to move in the axial direction AA, so that: when the first plate 30 or the second plate 33 rotates, the rolling element 32 rolls while remaining in the second plate seat portion of the second plate 34, but the rolling element 32 rises along the ramp-shaped track 31, thereby causing the second plate 33 or the first plate 30 to move axially.

[0206] According to an embodiment, the nut 281, or the first plate 30, or the second plate 33 of the rotation-linear motion conversion device 12 is arranged to abut against an axial thrust bearing 35, which resists displacement of the nut 281, or the first plate 30, or the second plate 33 of the rotation-linear motion conversion device 12 in the axial direction AA:

[0207] According to an embodiment, said rotational-linear motion conversion means 12 are connected to wear recovery means 47 of said at least one pad 3 .

[0208] According to an embodiment, the nut 281, or the first plate 30, or the second plate 33 of the rotational-linear motion conversion device 12 is configured to abut against an axial thrust bearing 35, which resists the displacement of the nut 281, or the first plate 30, or the second plate 33 of the rotational-linear motion conversion device 12 in the axial direction AA; and the axial thrust bearing 35 is configured to directly or indirectly abut against the wear recovery device 47 of the at least one pad 3.

[0209] According to an embodiment, said thrust bearing 35 is arranged to bear directly or indirectly against the force sensor 46 .

[0210] According to an embodiment, said wear recovery means 47 of said at least one pad 3 is arranged on a force sensor 46 .

[0211] According to an embodiment, the linear actuator device 1 comprises a cover receiving portion 36 , which receives and supports the stator 8 of the motor 6 .

[0212] According to an embodiment, the linear actuator 1 includes a cover accommodating portion 36, which supports and accommodates a motor sleeve 37. The motor sleeve 37 supports a radial motor roller support 38 in a keyed manner, and the radial motor roller support 38 supports the rotating drive shaft 7 of the motor 6.

[0213] According to an embodiment, the linear actuator device 1 comprises a cover housing 36 supporting the static ring 26 of the harmonic drive 10 .

[0214] The cover member accommodation portion 36 is formed as a cylindrical member, which can be assembled into / disassembled from the caliper body seat portion 39 provided in the brake caliper 2, while at least the motor component 6, the harmonic transmission device 10 and the rotation-linear motion conversion device 12 accommodated in the cover member accommodation portion 36 are retained.

[0215] According to an embodiment, said rotational-linear motion conversion device 12 is connected in a linked manner to a push plate 40 adapted to be arranged on said at least one brake pad 3 .

[0216] The invention also relates to a brake caliper 2 comprising at least one linear actuating device 1 according to any of the above-described embodiments; wherein the brake caliper has one of the following features:

[0217] - The brake caliper 2 is a floating brake caliper;

[0218] The brake caliper 2 is a fixed brake caliper, and the linear actuating device 1 comprises at least two opposing linear actuating devices 1 .

[0219] In order to meet specific and accidental needs, those skilled in the art may make various changes and modifications to the above-described embodiments, and may replace elements with other functionally equivalent elements without departing from the scope of the appended claims.

[0220] According to a general embodiment, the caliper body 50 of the brake caliper comprises at least one component shaped as a closed-loop yoke.

[0221] Said component 51 is yoke-shaped and has a component outer side 52 and an opposite component inner side 53 adapted to face the brake disc 5 .

[0222] Said component 51 comprises at least one caliper body seat 39 .

[0223] The caliper body seat portion 39 is a through-seating portion extending from the component outer portion 52 to the component inner portion 53 .

[0224] The caliper body seat 39 accommodates the linear actuator 1 in a removable manner.

[0225] The linear actuator 1 is housed in the caliper body seat 39 so as to pass through the component 51 and is adapted to interact with the brake pad 3 to apply a braking action to the brake disc 5 .

[0226] According to an embodiment, said component 51 is a floating caliper body 41 .

[0227] According to an embodiment, said component 51 is a fixed caliper body comprising at least two caliper body seats 39 facing each other.

[0228] According to an embodiment, at least one of said caliper body seats 39 comprises an outer seating skirt 54 .

[0229] The outer seating skirt 54 is cylindrical in shape.

[0230] At least one axially extending section XX of said outer seating skirt 54 is completely free, except for two component ribs 55, 56 spaced apart from said outer seating skirt 54. According to an embodiment in which at least one of said caliper body seats 39 is formed on the opposite side of the caliper body, at least one axially extending section XX of said outer seating skirt 54 is completely free, except for two component ribs 55 spaced apart from said outer body skirt 54.

[0231] According to an embodiment, the at least one caliper body seat 39 comprises an outer seating skirt 54 .

[0232] The outer seating skirt 54 is cylindrical in shape.

[0233] Apart from two component ribs 56 which are spaced apart from the outer seating skirt 54 and form an angle of about 160 degrees therebetween, at least one axially extending section XX of the outer seating skirt 54 is completely free.

[0234] According to an embodiment, the at least one caliper body seat 39 comprises an outer seating skirt 54 .

[0235] The outer seating skirt 54 is cylindrical in shape.

[0236] Apart from two component ribs 56 which are spaced apart from the outer seating skirt 54 and form the yoke-shaped component 51 , at least one axially extending section XX of the outer seating skirt 54 is completely free.

[0237] According to an embodiment, the at least one caliper body seat 39 comprises an outer seating skirt 54 .

[0238] The outer seating portion skirt 54 is cylindrical in shape.

[0239] Apart from two component ribs 56 spaced apart from the outer seating skirt 54 , at least one axially extending section XX of the outer seating skirt 54 is completely free.

[0240] The cylindrical outer seating skirt 54 defines an outer cylindrical surface 57 that projects beyond the two component ribs 56 in the outer radial direction RE over an arc of more than 180 degrees of its cross section in circumferential CC and radial RR planes.

[0241] According to an embodiment, said at least one caliper body seat 39 comprises an internal connection thread 58 for a cylinder for removably connecting said linear actuating device 1 provided with a corresponding external connection thread 59 for a cylinder.

[0242] According to an embodiment, said at least one caliper body seat 39 comprises an axial annular abutment 60 protruding towards the inside of said at least one caliper body seat 39 to abut against said linear actuation device 1 .

[0243] According to an embodiment, the yoke-shaped component 51 includes: an elongated element 61 on the vehicle side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the vehicle; and an elongated element 62 on the wheel side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the wheel.

[0244] The yoke-shaped component 51 comprises at least one component rib 55 , 56 which extends 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 .

[0245] According to an embodiment, the yoke-shaped component 51 includes: an elongated element 61 on the vehicle side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the vehicle; and an elongated element 62 on the wheel side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the wheel.

[0246] The yoke-shaped component 51 comprises at least one component rib 55 , 56 which extends circumferentially along the extension of the vehicle-side elongated element 61 and along the extension of the wheel-side elongated element 62 .

[0247] The radial height RR of said at least one component rib 55 , 56 is smaller than the overall radial height RR of said yoke-shaped component 51 , except for the portion of the body that delimits said caliper body seat 39 .

[0248] According to an embodiment, said component 51 is a floating caliper body 41 .

[0249] The floating caliper body comprises sliding guide seats 63, 64 adapted to accommodate sliding pins 65, 66 connected to a floating brake caliper bracket 42 adapted to be connected to a vehicle.

[0250] The slide guide seating portions 63 , 64 protrude from the floating caliper body 41 in the outer radial direction RE.

[0251] According to an embodiment, the yoke-shaped component 51 includes: an elongated element 61 on the vehicle side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the vehicle; and an elongated element 62 on the wheel side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the wheel.

[0252] The vehicle-side elongated element 61 and the wheel-side elongated element 62 are connected to one another at least via two end bridges 67 , 68 .

[0253] The vehicle-side elongated element 61 and the wheel-side elongated element 62 comprise a component inner side or floating body inner side 53 .

[0254] The component inner side or floating body inner side 53 comprises two ridges 69 , 70 which project inwardly to form pad abutment shoulders 71 , 72 forming a pad seating portion 73 therebetween.

[0255] According to an embodiment, the yoke-shaped component 51 includes: an elongated element 61 on the vehicle side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the vehicle; and an elongated element 62 on the wheel side, which is suitable for facing the brake disc 5 on the side of the brake disc 5 facing the wheel.

[0256] The vehicle-side elongated element 61 and the wheel-side elongated element 62 are connected to one another at least via two end bridges 67 , 68 .

[0257] Each of the vehicle-side elongated element 61 and the wheel-side elongated element 62 comprises a component inner side or floating body inner side 53 .

[0258] The component inner side or floating body inner side 53 comprises two ridges 69 , 70 which project inwardly to form pad abutment shoulders 71 , 72 forming a pad seating portion 73 therebetween.

[0259] The pad abutment shoulders 71 , 72 converge as they extend in the inner radial direction RI so as to approach each other.

[0260] The present invention further relates to a brake caliper 2 , which comprises a caliper body 50 according to any one of the above-mentioned embodiments.

[0261] According to an embodiment, the linear actuation device 1 made according to any one of the embodiments described above is housed in said at least one caliper body seat 39 in a removable manner.

[0262] Reference numerals list

[0263] 1 Linear actuator

[0264] 2 Brake calipers

[0265] 3 Brake pads

[0266] 4 Braking surfaces

[0267] 5 Brake disc

[0268] 6 Motor

[0269] 7 Rotating drive shaft

[0270] 8 Stator

[0271] 9 Rotational wave generator

[0272] 10 Harmonic drive or strain wave drive

[0273] 11 Harmonic reducer

[0274] 12Rotation-Linear Motion Converter

[0275] 13 Tubular body of drive shaft

[0276] 14 Internal cavity of drive shaft

[0277] 15 Permanent magnets for drive shaft

[0278] 16 First section of drive shaft

[0279] 17 Drive shaft support seat

[0280] 18 Oval support rotating ring

[0281] 19 Elliptical bearing rolling element

[0282] 20 External oval supporting rotating ring

[0283] 21 Oval support

[0284] 22 Flexible cup

[0285] 24 Flexible portion of the flexible cup

[0286] 25 Cup tooth

[0287] 26 Static ring

[0288] 27 Ring tooth

[0289] 28 Cup-shaped connecting part

[0290] 281 Nut

[0291] 29 Worm or recirculating ball worm

[0292] 30 First Board

[0293] 31 Sloping track

[0294] 32 Plate rolling element

[0295] 33 Second board

[0296] 34 Second plate seat

[0297] 35 Axial thrust bearing

[0298] 36 Covering member receiving portion

[0299] 37 Motor sleeve

[0300] 38 Radial motor bearing

[0301] 39 Caliper body seat

[0302] 40 is suitable for setting a push plate on the brake pad

[0303] 41 Floating body of floating brake caliper

[0304] 42 floating brake caliper bracket

[0305] 43 Elastic means for moving the pad away from the brake disc

[0306] 44 Brake disc bell

[0307] 45 Dust seal

[0308] 46 Force Sensor

[0309] 47 Wear recovery device

[0310] 48 Threaded portion for connecting the caliper of the cover receiving portion

[0311] 49 The corresponding threaded part of the caliper body seat

[0312] 50 Caliper body

[0313] 51 Floating body or yoke

[0314] 52 The outer side of the component or the outer side of the floating body

[0315] 53 The inside of the component or the inside of the floating body

[0316] 54 Outer seating skirt

[0317] 55 Component rib

[0318] 56 Component rib

[0319] 57 outer cylindrical surface

[0320] 58 Internal connection thread for cylinder

[0321] 59 The cylinder of the linear actuator is connected to the corresponding threaded part with an external connection

[0322] 60 Axial annular abutment portion of the caliper body seat

[0323] 61 Long element on vehicle side

[0324] 62 Long element on wheel side

[0325] 63 Sliding guide

[0326] 64 Sliding guide

[0327] 65 Sliding pin

[0328] 66 Sliding pin

[0329] 67 End bridge

[0330] 68 End bridge

[0331] 69 Ridges

[0332] 70 Ridges

[0333] 71 Pad against shoulder

[0334] 72 Pad against shoulder

[0335] 73 Seating area

[0336] XX Rotation axis

[0337] AA Axial direction

[0338] RR Radial direction

[0339] CC Circumferential direction

[0340] MM Motor axis

[0341] RE Outer radial direction

[0342] RI Inner radial direction.

Claims

1. A linear actuation device (1) for a brake caliper (2), the linear actuation device (1) being adapted to bias at least one brake pad (3) so that the at least one brake pad (3) abuts against a braking surface (4) of a brake disc (5), wherein: The device comprises: A motor (6), the motor (6) comprising a rotating drive shaft (7) and a stator (8); A harmonic transmission device (10), the harmonic transmission device (10) comprising: A rotating wave generator (9) of the strain wave transmission element of the harmonic transmission device (10), wherein the rotating wave generator (9) is referred to as a wave generator; The rotary wave generator (9) is at least partially made in one piece with the rotary drive shaft (7); A harmonic reducer (11) of the harmonic transmission device (10); The harmonic reducer (11) is elastically deformed and rotated by the rotary wave generator (9); a rotational-linear motion conversion device (12) adapted to convert a rotational motion into a linear motion and adapted to bias the at least one brake pad (3) along an axial direction (AA) so that the at least one brake pad (3) abuts against the brake surface (4); The rotation-linear motion conversion device (12) is rotatably connected to the harmonic reducer (11).

2. The linear actuator (1) according to claim 1, wherein: The harmonic transmission device (10) is stacked on the rotation-linear motion conversion device (12); or among them, The rotary-linear motion conversion device (12) comprises a nut (281) meshing with a worm (29), the worm (29) translating along the axial direction (AA) when the nut (281) rotates; and wherein, The harmonic drive device (10) is stacked on the nut (281).

3. The linear actuator (1) according to claim 1 or 2, wherein: The drive shaft (7) has a tubular body (13) forming a drive shaft interior chamber (14); and wherein, The rotary-to-linear motion conversion device (12) is at least partially housed within the drive shaft interior chamber (14) when in a retracted position.

4. A linear actuator (1) according to any one of the preceding claims, wherein: The rotary-to-linear motion conversion device (12) is at least partially housed within the drive shaft interior chamber (14) when in a retracted position; and / or where The rotary-linear motion conversion device (12) is accommodated in the tubular body (13) of the drive shaft (7) in a radial direction relative to the axis of the tubular body; and / or wherein, When the rotary-to-linear motion conversion device (12) is in a retracted state, the rotary-to-linear motion conversion device (12) is completely accommodated in the drive shaft internal chamber (14), except for a push plate or an extension of the rotary-to-linear motion conversion device (12) that is suitable for being arranged on a brake pad, and the push plate protrudes outward to interact with the brake pad.

5. A linear actuator (1) according to any one of the preceding claims, wherein: The linear actuator (1) has one of the following features or a combination of the following features: - the motor (6) is an electric motor; - the motor (6) is a brushless electric motor, for example a so-called BLDC; - the motor (6) is a brushless electric motor and the rotary drive shaft (7) comprises permanent magnets (15); - the motor (6) is a brushless electric motor and the rotary drive shaft (7) comprises a permanent magnet (15) comprising a neodymium; And wherein the motor (6) is a brushless electric motor, and the rotary drive shaft (7) includes a permanent magnet (15) embedded in the body of the rotary drive shaft (7).

6. A linear actuator (1) according to any one of the preceding claims, wherein: - the rotating wave generator (9) is an elliptical support (21); and / or where - The rotating drive shaft (7) includes at least one driving shaft support seat (17); the driving shaft support seat (17) is concentric with the rotation axis (MM) of the motor, and the rotation axis (MM) of the motor is parallel to the axial direction (AA); and wherein the rotating drive shaft (7) is formed in an integral manner with an elliptical supporting rotating ring (18), and the elliptical supporting rotating ring forms an elliptical orbit; and wherein the elliptical supporting rolling element (19) and the external elliptical supporting rotating ring (20) are associated with the elliptical supporting rotating ring (18) to form an elliptical supporting member (21).

7. A linear actuator (1) according to any one of the preceding claims, wherein: The harmonic transmission device (10) includes a harmonic reducer (11); and wherein the harmonic reducer (11) includes a flexible cup (22) and a static ring (26); and wherein the flexible cup (22) includes a flexible portion (24) of the flexible cup, the flexible portion (24) of the flexible cup is called a flexible key, an elliptical support (21) that elastically deforms the flexible portion (24) of the flexible cup is keyed to one side of the flexible portion (24) of the flexible cup, and wherein the flexible portion (24) of the flexible cup includes a cup tooth portion (25) on the opposite side; and wherein the harmonic reducer (11) includes a ring-shaped static ring (26); and wherein the static ring (26) includes a ring tooth portion (27); and wherein, in the deformed When the flexible cup (22) has a maximum diameter, the cup teeth (25) mesh with the ring teeth (27); and wherein the cup teeth (25) are less in number than the ring teeth (27) so that: when the flexible portion (24) of the flexible cup is deformed, 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; and wherein the linear actuation device (1) includes a cover receiving portion (36); and wherein the static ring (26) is fixedly keyed to the caliper housing of the brake caliper (2), or the static ring (26) is fixedly keyed to the cover receiving portion (36).

8. A linear actuator (1) according to any one of the preceding claims, wherein: The harmonic transmission device (10) comprises a harmonic reducer (11); wherein the harmonic reducer (11) comprises a flexible cup (22) and a static ring (26) which mesh with each other at at least two points; and wherein the flexible cup (22) comprises a cup connecting portion (28) to be keyed to the rotation-linear motion conversion device (12).

9. A linear actuator (1) according to any one of the preceding claims, wherein: The harmonic transmission device (10) includes a harmonic reducer (11); wherein the harmonic reducer (11) includes a flexible cup (22) and a static ring (26) that mesh with each other at at least two points; wherein the flexible cup (22) includes a cup connecting portion (28) formed by a tubular sleeve; wherein the cup connecting portion (28) formed by the tubular sleeve is keyed to a nut (281); the nut (281) is supported to rotate freely and is axially restricted to prevent the nut (281) from moving along the axial direction (AA); and wherein the nut (281) meshes with a worm (29), and the worm (29) translates along the axial direction (AA) when the nut (281) rotates.

10. A linear actuation device (1) according to any one of the preceding claims, wherein: The harmonic transmission device (10) comprises a harmonic reducer (11); wherein the harmonic reducer (11) comprises a flexible cup-shaped member (22) and a static ring-shaped member (26) which are meshed with each other at at least two points; and wherein, The flexible cup-shaped member (22) includes a cup-shaped member connecting portion (28); the cup-shaped member connecting portion (28) is connected to the rotation-linear motion conversion device (12); and wherein the cup-shaped member connecting portion (28) is mainly arranged in the inner chamber (14) of the drive shaft; and wherein the rotation-linear motion conversion device (12) includes a nut (281), and the nut (281) accommodates a worm (29); the worm (29) is engaged in the nut (281) and converts the rotational motion of the nut (281) into the linear motion of the worm (29).

11. A linear actuator (1) according to any one of the preceding claims, wherein: The rotation-linear motion conversion device (12) includes a nut (281) which accommodates a recirculating ball worm (29), the worm (29) being engaged in the nut (281) and converting the rotational motion of the nut (281) into the linear motion of the worm (29).

12. A linear actuator (1) according to any one of the preceding claims, wherein: When the rotary-linear motion conversion device (12) is in the retracted position, the rotary-linear motion conversion device (12) is substantially completely accommodated in the drive shaft inner chamber (14).

13. A linear actuator (1) according to any one of the preceding claims, wherein: The harmonic transmission device (10) comprises a harmonic reducer (11); wherein the harmonic reducer (11) comprises a flexible cup-shaped member (22) and a static ring-shaped member (26) which are meshed with each other at at least two points; and wherein, The flexible cup (22) includes a cup connection portion (28); the cup connection portion (28) is connected to a first plate (30); and wherein The first plate (30) comprises a ramp-like track (31) extending circumferentially around the axial direction (AA) and gradually extending along the axial direction (AA); and wherein, The first plate (30) is constrained in translation along the axial direction (AA) to avoid axial movement of the first plate (30), and the first plate (30) is free to rotate about the axial direction (AA); and wherein, The ramp-shaped track (31) accommodates a plate rolling element (32), which is, for example, a ball or a roller; and wherein, The first plate (30) faces the second plate (33); the second plate (33) includes a second plate seat (34) for accommodating the plate rolling element (32), wherein the second plate seat (34) faces the ramp-shaped track (31).

14. Linear actuator (1) according to the preceding claim, wherein: The first plate (30) or the second plate (33) is restricted in translation along the axial direction (AA) to avoid axial movement of the first plate (30) or the second plate (33), and the first plate (30) or the second plate (33) is free to rotate around the axial direction (AA); and wherein, The second plate (33) or the first plate (30) is restricted in rotation, and the second plate (33) or the first plate (30) is free to move along the axial direction (AA) so that: when the first plate (30) or the second plate (33) rotates, the rolling element (32) rolls while remaining in the second plate seat portion of the second plate (34), but the rolling element (32) rises along the ramp-shaped track (31), thereby causing the second plate (33) or the first plate (30) to move axially.

15. A linear actuation device (1) according to any one of the preceding claims, wherein: - the rotary-linear motion conversion device (12) comprises a nut (281) for accommodating a recirculating ball worm (29), or the rotary-linear motion conversion device (12) comprises a first plate (30) and a second plate (33), at least one of the first plate (30) and the second plate (33) comprising a ramp-shaped track (31) for accommodating a plate rolling element (32); and wherein, The nut (281), or the first plate (30), or the second plate (33) of the rotation-linear motion conversion device (12) is arranged to abut against an axial thrust bearing (35), and the axial thrust bearing resists displacement of the nut (281), or the first plate (30), or the second plate (33) of the rotation-linear motion conversion device (12) in the axial direction (AA); and / or where - the rotational-linear motion conversion device (12) is connected to a wear recovery device (47) of the at least one pad (3); and / or where -The rotational-linear motion conversion device (12) includes a nut (281) for accommodating a circulating ball worm (29), or the rotational-linear motion conversion device (12) includes 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-shaped track (31), and the ramp-shaped track (31) accommodates a plate rolling element (32); and wherein the nut (281), or the first plate (30), or the second plate (33) of the rotational-linear motion conversion device (12) is arranged to abut against an axial thrust bearing (35), and the axial thrust bearing resists displacement of the nut (281), or the first plate (30), or the second plate (33) of the rotational-linear motion conversion device (12) in the axial direction (AA); and the axial thrust bearing (35) is arranged to directly or indirectly abut against a wear recovery device (47) of at least one pad (3).

16. A linear actuation device (1) according to any one of the preceding claims, wherein: The linear actuator (1) has one or a combination of the following features: - the linear actuator (1) comprises a cover receiving portion (36) for receiving and supporting the stator (8) of the motor (6); - the linear actuator (1) comprises a cover receiving portion (36) supporting and receiving a motor sleeve (37), wherein the motor sleeve (37) supports a radial motor support (38) in a keyed manner, wherein the radial motor support (38) supports the rotating drive shaft (7) of the motor (6); - the linear actuating device (1) comprises a cover receiving portion (36) supporting a static annular member (26) of the harmonic transmission device (10); and wherein the cover receiving portion (36) is formed as a cylinder, which can be assembled to / detached from a caliper body seat (39) provided in the brake caliper (2), and at the same time, the cylinder retains at least the motor component (6), the harmonic transmission device (10) and the rotation-linear motion conversion device (12) accommodated in the cover receiving portion (36); The rotary-linear motion conversion device (12) is connected in a linked manner to a push plate (40) adapted to be arranged on the at least one brake pad (3).

17. A brake caliper (2), comprising at least one linear actuation device (1) according to any one of claims 1 to 16; wherein: The brake caliper (2) has any one of the following features: - the brake caliper (2) is a floating brake caliper; The brake caliper (2) is a fixed brake caliper, and the linear actuating device (1) comprises at least two opposing linear actuating devices (1).

18. A disc brake comprising a brake caliper (2) according to claim 18, the brake caliper (2) being arranged to straddle a brake disc (5).

Images