Electric brake actuator, brake and assembly method, in particular for a

Abstract

The invention relates to an electric brake actuator. A motor (11) drives, at an end thereof, an input sun gear (12) of a differential planetary reduction gear set of which planetary gears (22) mesh with a fixed ring gear (21) and a movable ring gear (23). Thus, the reduction gear set provides irreversibility and is combined in series with a reversible screw-nut mechanism (31-32). Advantageously, the movable ring gear rotates the nut, thereby translating (F1) the fixed screw to prevent it from rotating. The input gear advantageously has an axial housing (120) that receives the screw when the screw is retracted. The motor has an outer rotor mounted in an outer rolling bearing (15), and the screw housing (120) extends axially within the stator (111). A common centering support (16) carries the motor bearings and the fixed ring gear. A movable ring gear and screw-nut mechanism (3) is fitted on either side of a housing (410) passing through the caliper.

Description

[0001] The invention relates to an electric brake actuator, in particular for disc brakes, in particular sliding caliper brakes, and particularly suitable for fully electric operation. The motor drives at its end the input sun gear of a differential planetary reduction gear set, the planetary gears of which mesh with a fixed annular gear and a movable annular gear. The reduction gear set thus provides irreversibility and is combined in series with a reversible screw-nut mechanism.

[0002] Advantageously, the movable annular gear causes the fixed nut to perform a translational rotation, which in turn causes the screw, which is fixed against rotation by the piston and the sleeve, to perform a translational rotation. The input sun gear advantageously has an axial recess which receives the screw when it is retracted. Preferably, the motor has an outer rotor mounted in an external rolling bearing, the screw recess extending axially in the stator. A common centering support, in particular an attachment, carries the motor bearings and the fixed annular gear. The movable annular gear and the screw-nut mechanism are assembled on both sides of a recess passing through the caliper and are rotatably coupled in said recess, the rear opening of which receives the motor unit.

[0003] The invention also relates to a disc brake comprising such an actuator, in particular for the production of a parking brake, and a method for assembling such a brake. Background Art

[0004] Previously, a "coaxial gear motor" architecture was proposed in document US4804073. This document proposes a "differential" reduction gear set, in which two planetary gear trains share the same set of "common" planetary gears, all of which are meshed on two different ring gears, one of which is fixed and the other is movable. These planetary gears are driven by the sun gear on the input side, and the two ring gears have a different number of teeth from each other, so that the movable ring gear is driven to form an output with a very high transmission ratio. The movable ring gear causes a screw located in the piston to rotate, which causes the fixed nut to translate, thereby translating the piston.

[0005] However, this architecture takes up considerable space in the axial direction, making it difficult to integrate into the vehicle.

[0006] More recently, document FR3031154 proposes another "coaxial" architecture, the upstream epicyclic stage of which uses the same fixed annular gear as the first differential gear train. In this configuration, the three planetary gear trains are housed inside the piston, the mobile annular gear forming the screw that drives in translation the nut of the screw-nut mechanism, the nut being formed by the brake piston itself.

[0007] However, this solution still requires a certain axial space and can present considerable difficulties and limitations, for example in terms of industrialization or load-bearing capacity.

[0008] Another arrangement with a "transverse gear motor" is known from document FR 2 999 257 A1. In this gear motor, the motor axis is parallel to the output of the reduction gear set and is laterally offset.

[0009] In this configuration, the brake piston is driven linearly (clamped "forwards") by a stationary nut that is prevented from turning, which in turn is moved by the rotation of a screw inside the piston. This screw is driven at the input end by the "rear" of the brake via a gear motor. This motor is equipped with a coaxial epicyclic motor and reduction gear, whose axis is offset from the screw axis and whose output direction is "backwards". This architecture is currently used in many vehicles, but takes up considerable space, especially on the sides.

[0010] The object of the invention is to overcome all or part of the disadvantages of the prior art. In particular, the object is to improve compactness, simplify integration into different types of vehicles, make manufacturing simpler and less expensive, and / or optimize the trade-offs between these factors. These objects are achieved by using various components and methods, taking into account the constraints prevailing in the field of motors and actuators, in particular in the automotive industry and its braking sector; in particular in terms of reliability, simplicity, flexibility and cost of manufacturing, maintenance and / or design, while optimizing performance, for example in terms of efficiency and / or flexibility of mechanical or acoustic operation. Summary of the invention

[0011] To this end, the invention proposes a linear brake actuator, in particular a disc brake actuator, driven by an electric motor, in particular for road and / or motor vehicles, the actuator being mounted or intended to be mounted in a brake housing, in particular a caliper housing, the brake housing having a through recess between a front side facing the disc and a rear side opposite the front side.

[0012] According to the invention, the actuator comprises a differential planetary reduction gear set coaxial with the motor, the differential planetary reduction gear set being driven at the input end by a sun gear, the sun gear driving a set of planetary gears, each of the planetary gears being meshed with both a fixed annular gear and a movable annular gear, the annular gears having different numbers of teeth from each other.

[0013] The movable ring gear rotates a reversible screw-nut mechanism which produces a linear drive of the brake piston between a retracted position and an extended position, thereby applying a linear pressure in the so-called forward direction to produce a clamping force on the disc between the clamping pads, which is irreversible at the differential planetary reduction gear set, that is, even if the screw-nut mechanism itself does not exhibit such irreversibility, the linear force exerted on the brake piston in the release direction will be blocked by the actuator independently of the electric motor.

[0014] In fact, although according to a purely theoretical approach the fundamental principle of this kinematics is reversible, the inventors have discovered that this kinematics can in fact present an irreversible operation, at least under the conditions in which it is arranged so as to obtain a size and reduction suitable for such a brake actuator.

[0015] This irreversibility is achieved in particular at reduction ratios greater than 20, in particular greater than or equal to 28 or even 30. Tests were carried out with values ​​of the ratio of 28, 30, 36, 54.2, 60 and 88.

[0016] This makes it possible to produce a non-reversible brake actuator while providing a screw-nut mechanism that is inherently reversible and is therefore more efficient than a non-reversible screw-nut assembly. This makes it possible, for example, to produce a reliable electric parking brake that consumes no energy when parking but is energy-efficient when starting. This not only saves energy, but also improves space requirements and / or reliability, since higher efficiency means, for example, that a less powerful motor can be selected and / or higher reliability can be achieved.

[0017] For example, such a differential planetary reduction gear set provides an energy efficiency in the range of 50% to 70%. Here, the gear set is combined in series with a reversible screw-nut assembly with an efficiency of about 85% to 90%. This makes the overall efficiency exceed 42%.

[0018] The overall energy efficiency of the present application is higher than the latest combination of an irreversible screw-nut assembly with an efficiency of less than 35% and a conventional epicyclic gear train with a gear efficiency of about 90%, which has an overall efficiency of less than 31%.

[0019] Preferably, the movable annular gear and the fixed annular gear have a difference of at least three teeth, or even at least five teeth. Preferably, the difference does not exceed seven teeth, or even does not exceed five teeth. Typically, the difference in the number of teeth is a multiple of the number of planetary gears.

[0020] According to a preferred feature of the invention, but which can also be implemented independently of the irreversible aspect, the nut of the screw-nut mechanism is fixed against translation and driven in rotation by the movable ring gear, and the nut of the screw-nut mechanism engages with a screw fixed against rotation to cause translational movement of said screw, thereby generating said linear drive. When in the retracted position, the screw extends axially in a recess provided in said input sun gear.

[0021] As a result, better axial compactness is achieved and also the ability to produce longer screws with the same external axial dimensions is obtained. This makes it possible, for example, to achieve a better compromise between axial compactness, stroke length and guiding accuracy.

[0022] For example, for the same axial footprint, this architecture with a screw through a hollow sun gear enables the stroke to be increased from 18 mm to 43 mm, which is an additional 25 mm of stroke, or 5 more turns if the pitch is 5 mm. This provides, for example, greater margin to compensate for bushing wear and enables the use of thicker bushings, and / or reduces the axial size of the actuator and brake.

[0023] According to a first particular series of embodiments, the linear brake actuator comprises an outer rotor type motor, for example, whose stator is fixed in a motor housing by end cross flanges. In addition, the input sun gear is driven by the rotor and carried by a shaft, which is guided in rotation by one or more rolling bearings mounted in the stator.

[0024] Thus, a simple, robust architecture is obtained.

[0025] According to a preferred example of this first series of embodiments:

[0026] The motor has an inner stator and an outer rotor; and

[0027] an input sun gear fixed to the rotor and carried by a shaft extending within the stator or integral to the shaft, which is guided in rotation by antifriction bearings; and

[0028] The movable ring gear preferably rotates within the fixed ring gear or its centering support; and

[0029] The movable ring gear is rotationally attached to the nut by longitudinal splines or engagement of teeth or grooves (strictly longitudinal, or less than 20° or even less than 10°); and

[0030] The fixed ring gear is mounted in or around a recess in the brake housing or a housing attached thereto,

[0031] the nut being mounted for free rotation in a bore in the brake housing, the bore terminating in a shoulder having a forwardly facing bearing surface against which the nut abuts axially; and

[0032] The screw is fixed to a support plate which forms a brake piston and holds the screw fixed in rotation, in particular by rotationally coupling the piston with a brake pad which receives the linear force of the piston and which is itself held fixed in rotation by a fixed bracket.

[0033] According to a second particular series of embodiments, the linear brake actuator comprises an outer rotor type motor and its rotor is guided in rotation in one or more rolling bearings mounted in the bore of at least one centering support fixed to the fixed annular gear (in any way, for example, as a single piece or in assembled form).

[0034] The result is better compactness and / or better centering of the motor and / or various drive train components, for example, between the motor rotor and the input sun gear of the differential reduction gear set.

[0035] According to an advantageous but optional feature, the screw of the screw-nut mechanism extends axially in a stator recess provided in the stator. This makes it possible to further improve the axial compactness and / or length of the screw and thus the stroke. According to a preferred example of this second series of embodiments:

[0036] The motor has an inner stator and an outer rotor; and

[0037] The rotor is guided in rotation by an outer bearing mounted in the centering element and is rotationally fixed to the input sun gear and preferably also translationally fixed to the input sun gear; and

[0038] The stator is hollow, i.e. it has an axial recess over at least half of the length of the motor, preferably over the entire length of the motor, which axial recess is designed to allow the screw to pass through the input sun gear and the interior of the stator;

[0039] the fixed annular gear is mounted on or integrated into a centering support which accommodates at least one of the motor rolling bearings or forms part of said motor rolling bearing, that is to say, the centering support is made of a single material or has material continuity between the part forming or accommodating said motor bearing and the part forming or accommodating the fixed annular gear; and the movable annular gear is rotationally attached to the nut by means of a longitudinal spline or tooth or groove engagement (strict or less than 20° or even less than 10°); and

[0040] The fixed ring gear or its centering support is mounted in or around a recess in the brake housing,

[0041] the nut being mounted for free rotation in a bore in the brake housing, the bore terminating in a shoulder having a forwardly facing bearing surface against which the nut abuts axially; and

[0042] The screw is fixed to a support plate which forms a brake piston and holds the screw fixed in rotation, in particular by rotationally coupling the piston with a brake pad which receives the linear force of the piston and which is itself held fixed in rotation by a fixed bracket.

[0043] According to another optional advantageous feature, which may or may not be combined with the aforementioned features, the same centering support, produced in a single piece (i.e. with material continuity, for example by overmolding or welding) and in particular from a single material (e.g. by molding or machining a single initial block of material), carries and / or forms both the fixed annular gear and the guide bearing for the rotor.

[0044] Advantageously, the motor is attached to the housing via a common centering support, which is in particular made of plastic or an aluminum alloy. The housing is typically a motor housing mounted on a brake housing, or directly the brake housing itself.

[0045] This makes it easier to obtain high-performance centering supports while optimizing manufacturing constraints and enabling a modular range that simplifies the design and manufacturing or maintenance process.

[0046] Another advantageous optional feature (which may or may not be combined with the previous features) is that the screw is fixed to a support plate acting as a brake piston, which transmits the linear actuation to at least one clamping pad. Typically, the support plate covers the junction area between the screw and the nut, since it protrudes radially beyond this junction area.

[0047] More specifically, the nut is arranged to be guided in rotation by one or more rolling bearings, in particular roller bearings or needle bearings, mounted in holes provided in the caliper housing; and the nut is arranged to be guided in axial translation by at least one anti-friction bearing, in particular roller bearing or needle bearing, against an axial bearing surface of a shoulder of the caliper housing facing forward, the at least one anti-friction bearing being arranged between the front surface and a portion of the nut extending radially to form a bearing flange.

[0048] According to various features intended to be used in combination or separately, and having all or some of the optional features described herein: the fixed ring gear is fixed to a skirt extending toward and around the movable ring gear;

[0049] The differential reduction gear set is mounted in a recess formed in the brake housing, in particular opening towards the rear, so that the reduction gear set can be mounted from the rear of the housing;

[0050] The motor is mounted in an external housing which is mounted in or around the brake housing, in particular in order to close a recess of the brake housing containing the reduction gear set;

[0051] The movable ring gear is guided for rotation by the interior of the fixed ring gear or its centering support;

[0052] A fixed annular gear is arranged in a bore of a brake housing recess, the fixed annular gear being radially retained in said bore by at least one cylindrical damper having at least radial damping, the damper being in particular formed entirely or partly from an elastomeric material, the cylindrical damper being compressed, for example, between the brake housing and a skirt fixed to the fixed annular gear, for example, extending towards and around the movable annular gear.

[0053] The actuators described herein enable all-electric brakes (ie, brakes that do not require or include hydraulic operation) to function as service brakes, emergency brakes, parking brakes, or any combination of these functions.

[0054] However, such an actuator can also be used in a version in which the threaded rod is linearly supported in a coaxial hydraulic piston which forms a selectively electrically and / or hydraulically actuated brake piston.

[0055] According to another aspect of the invention, a brake is proposed, in particular for road and / or motor vehicles, and a vehicle comprising such a brake, comprising an actuator as described herein. Brakes of this type are envisaged in all the different types of constructions known to date, for example, disc brakes, or disc brakes built into drum brakes, forming a "disc-in-drum" assembly.

[0056] According to an advantageous feature, all the different versions known so far provide a disc brake of the fixed, sliding or floating caliper type. The actuator is particularly suitable for integration in a disc brake, for example in terms of size and / or force / travel and speed capabilities, and is usually integrated in the caliper body or housing, which then acts as a "brake housing" for the actuator.

[0057] According to an advantageous characteristic, the disc brake is of the floating or sliding caliper type, comprising a caliper forming two arms designed to straddle at least one brake disc so as to apply a braking torque thereto by clamping at least two brake pads on the two faces of the disc. At least one of these arms comprises a body forming a caliper housing which produces the brake housing of the actuator. The caliper housing houses a linear actuation mechanism arranged to produce this clamping by linearly moving at least one brake piston pressed against at least one clamping pad. According to this characteristic, the linear actuation mechanism comprises at least one electric actuator as described herein, arranged to produce a linear clamping and releasing or pulling force at the rear of a support plate forming a brake piston, which does not employ hydraulic actuation (in particular, has no hydraulic actuation chamber).

[0058] Alternatively, the disc brake is of the floating or sliding caliper type, comprising a caliper forming two arms designed to span over at least one brake disc so as to apply a braking torque thereto by clamping at least two brake pads on the two faces of the disc. At least one of these arms comprises a body forming a brake housing which houses a linear actuation mechanism arranged to produce such clamping by linearly moving at least one brake piston pressing on at least one clamping pad. The linear actuation mechanism then comprises at least one electric actuator as described herein, arranged to produce the clamping force by linear abutment in a hydraulic piston housed in a hydraulic chamber controlled by a hydraulic circuit. For example, the hydraulic chamber is arranged around or in the axial extension of a hole housing the nut.

[0059] According to another aspect, the invention provides a method of manufacturing a brake actuator as described herein, or a brake comprising such an actuator, or a vehicle or a vehicle subassembly comprising such a brake.

[0060] According to one feature applied to a hollow sun gear actuator, the method advantageously comprises:

[0061] On the one hand, the shaft of a hollow sun gear is coaxially mounted with a bearing having one or more rolling bearings in a stator of an electric motor having an outer rotor, in particular by means of a press fit, so that a motor unit is formed, or such a motor unit is provided;

[0062] On the other hand, the following steps are included:

[0063] The movable ring gear is inserted into the rear side of the brake housing; and the assembly including the screw-nut mechanism is inserted into the front side of the brake housing. Insertion of the assembly including the screw-nut mechanism into the front side of the brake housing is achieved by mounting the movable nut of the screw-nut mechanism in a brake housing recess by means of at least one bearing, which guides the movable nut in rotation by means of a rolling bearing and guides the movable nut axially against the rear by means of a rolling bearing. For example, translational stability in both directions is achieved by a press fit between the bearing and the brake housing recess;

[0064] During or after insertion, in particular by engagement of the longitudinal grooves, a rotational coupling (around the screw and in the brake housing) and preferably also a translational coupling is effected between the movable ring gear and the movable nut, in particular by means of a circlip.

[0065] More specifically, in the case of an actuator having a common centering support (or even a support separate from the housing), the method advantageously comprises, on the one hand, assembling the motor unit or providing a motor unit assembled in this manner by:

[0066] On the one hand, the outer rotor of the motor is coaxially mounted with a bearing having one or more rolling bearings in a centering support, in particular by means of a press fit; on the other hand, the fixed ring gear of the differential planetary reduction gear set is coaxially mounted in the centering support, in particular by means of a press fit of a ring gear insert or by cutting the teeth of the ring gear directly into the material of the support element;

[0067] On the other hand, the following steps are included:

[0068] The movable ring gear is inserted into the rear side of the brake housing; and the assembly including the screw-nut mechanism is inserted into the front side of the brake housing. Insertion of the assembly including the screw-nut mechanism into the front side of the brake housing is achieved by mounting the movable nut of the screw-nut mechanism in a brake housing recess by means of at least one bearing, which guides the movable nut in rotation by means of a rolling bearing and guides the movable nut axially against the rear by means of a rolling bearing. For example, translational stability in both directions is achieved by a press fit between the bearing and the brake housing recess;

[0069] During or after insertion, in particular by engagement of the longitudinal grooves, a rotational coupling (around the screw and in the brake housing) and preferably also a translational coupling is effected between the movable ring gear and the movable nut, in particular by means of a circlip.

[0070] The invention provides various embodiments combining the different optional features described herein, according to all possible combinations thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Other features and advantages will become apparent from the detailed description of entirely non-limiting embodiments and from the accompanying drawings, in which:

[0072] [ Figure 1 ]: Figure 1 is a longitudinal cross-sectional view of an actuator according to a first example embodiment, the input sun gear of the actuator being located on a motor shaft mounted in a stator;

[0073] [ Figure 2 ]: Figure 2 Shows Figure 1 A top view of the assembly of the actuator;

[0074] [ Figure 3 ]: Figure 3 Shown include Figure 1 A scaled view of a longitudinal section of a fully electric disc brake in an example embodiment of an actuator;

[0075] [ Figure 4 ]: Figure 4 Shows Figure 1 An exploded perspective view to scale of an assembly example of an actuator is shown;

[0076] [ Figure 5 ]: Figure 5 shows a longitudinal cross-sectional view of an actuator according to a second example embodiment, the rotor of which is mounted on an external bearing;

[0077] [ Figure 6 ]: Figure 6 It is shown Figure 5 A top view of the assembly of the actuator;

[0078] [ Figure 7 ]: Figure 7 It is shown that Figure 5 A scaled view of a longitudinal section of a fully electric disc brake in an example embodiment of an actuator;

[0079] [ Figure 8 ]: Figure 8 Shows Figure 5 An exploded perspective view to scale of an assembly example of an actuator is shown;

[0080] [ Fig. 9 ]: Fig. 9 shows a longitudinal section through an actuator according to a variant of the second exemplary embodiment, the rotor bearing and the fixed annular gear of which are mounted on the same tube, forming a common centering element assembled with the motor housing;

[0081] [ Fig.10 ]: Fig.10 It is shown Fig. 9 A top view of the assembly of the actuator;

[0082] [ Fig.11 ]: Fig.11 It is shown that Fig. 9 A scaled view of a longitudinal section of a fully electric disc brake in an example embodiment of an actuator;

[0083] [ Fig.12 ]: Fig.12 It is shown that according to Figure 1 or Figure 5 or Fig. 9 A scaled perspective view of an example disc brake of an example embodiment of an actuator;

[0084] [Figure 13]: Figure 13 shows the Fig.12Scaled perspective view of certain subassemblies of the brake: reference numeral 13a relates to a differential reduction gear set with a fixed ring gear, reference numeral 13b relates to a differential reduction gear set without a fixed ring gear, reference numeral 13c relates to a screw-nut mechanism, reference numeral 13d relates to a caliper head as an insert. DETAILED DESCRIPTION

[0085] Figure 1 to Figure 1 3 shows an example embodiment of the present invention, in which the electric actuator uses a differential epicyclic reduction gear set 2, which drives a reversible screw-nut mechanism 3. This reversible screw-nut mechanism takes the form of a ball screw 32, in the threads of which balls 313 circulate to ensure its engagement with the nut 31.

[0086] The choice of a reversible screw-nut assembly provides good energy efficiency and greater freedom of pitch selection than when using an irreversible screw-nut assembly (as is the case with many known electric parking brakes). This choice is made possible by the irreversibility of the differential cyclic gearbox used.

[0087] In this example, the screw-nut mechanism 3 is driven in rotation by its nut 31 so that it moves in translation while holding the screw 32 immobile in rotation. However, the opposite is also possible, driving a known screw-nut mechanism with a differential epicyclic reduction gear set, wherein the screw is driven in rotation and is fixed against translation, while the nut is held against rotation but can move in translation.

[0088] First exemplary embodiment

[0089] Figures 1 to 4 A first example of an actuator for a sliding caliper disc brake is shown. Figure 1 and Figure 3 It can be seen that Figure 1 The actuator is mounted in the body 41 of the caliper 4 of the disc brake 51 and is mounted only on one side of the disc 509. In the clamping mode, the actuator applies a linear force F1 to the inner clamping pad 502, which presses on the inner friction surface of the disc 509, which in turn presses on the outer clamping pad 503, which in turn presses on the "nose" of the outer arm 42 of the caliper.

[0090] These clamping pads 502, 503 are guided in translation by a bracket 501 attached to the suspension part of the transmission gear, and are kept in rotation to transmit the braking torque. As is well known, the caliper 4 itself is mounted on the bracket 501 by means of a stud 504, which prevents the caliper 4 from rotating but allows free translation, so that the caliper 4 can move to distribute the clamping force on both sides of the disc, thus forming a "sliding caliper" architecture.

[0091] In this example, if Figure 3 Shown, in particular Figure 4 , Fig.12 As shown in FIG13 , the caliper itself consists of two distinct parts: a caliper body or caliper housing 41 and a nose insert 42, which are firmly connected to each other by a screw 43, for example, to facilitate the mounting of an actuator. However, this configuration is also designed for a one-piece caliper.

[0092] The motor 1 comprises a stator 111 which is clamped between a shoulder of the motor housing 10 and a shoulder of an intermediate cover 117 which also carries a circuit board 118 which controls the motor and integrates power electronics for powering the windings. The rear end of the intermediate cover 117 is closed by a heat sink cover 119 which is formed with the outside air to discharge the heat dissipated by the circuit board 118 through fins. For example, the heat sink cover 119 is made of a die-cast aluminum alloy and is usually in contact with the thermal components of the circuit board 118 via a thermally conductive paste.

[0093] In this example, the motor 1 is a type having an inner stator 111 and an outer rotor 112, and a DC motor having permanent magnets in the stator and magnetic windings in the stator is used as an example. However, other known motor types, such as conventional outer rotor type motors, may also be used.

[0094] The rotor 112 is fixed to the input sun gear 12 , which comprises a shaft 13 guided in rotation by rolling bearings 14 mounted in the tubular portion of the stator 111 .

[0095] The fixed ring gear 21 is attached to the motor housing 10, here by being mounted in a skirt 102 that protrudes axially from the front side of the motor housing. In this example, the fit is tight, with the prevention of rotation being achieved by cooperating shapes, in this case by the axial protrusions 211 protruding from the fixed ring gear cooperating with the voids in the skirt 102. Once the assembly is complete, the fixed ring gear 21 is mounted in a hole at the entrance to the brake housing recess 410.

[0096] The input sun gear 12 meshes with a set of planet gears 22 which are held in a cage of a planet carrier ring 220 .

[0097] These planetary gears 22 are long enough to mesh with both the fixed annular gear 21 and the movable annular gear 23, which is coaxial with the fixed annular gear and axially offset. In this example, the fixed annular gear 21 and the movable annular gear 23 have the same internal diameter and the modules of both are compatible with the teeth of the satellite gears, which are the same over the entire length of the satellite gears.

[0098] In this example, the movable ring gear 23 is guided in rotation, for example by lubricating friction, in a skirt 213 which projects axially from the fixed ring gear 21 and is coaxial therewith.

[0099] The number of teeth of the movable annular gear 23 is slightly different from that of the fixed annular gear 21, for example, 4 to 5 teeth. The movable annular gear 23 meshes with the planetary gears 22 supported on the fixed annular gear 21, and in this case, the movable annular gear 23 has the same number of teeth as the planetary gears 22, so that the movable annular gear 23 is driven to rotate by the planetary gears at a very low speed compared to the speed of the input sun gear 12.

[0100] In this example, advantageously but optionally, the motor 11 is attached to a motor housing 10 separate from the caliper 41. The motor housing 10 has an axial skirt 104 extending toward the front side and this skirt is fitted around a portion of the brake housing 41, forming a sleeve 401 extending from the rear side. This interlocking between the skirt 104 and the sleeve 401 fixes the motor housing 10 to the caliper housing 41, here with an anti-rotational engagement and translational retention by an external circlip 105.

[0101] Advantageously but optionally, the fixed annular gear 21 is arranged in the bore of a sleeve 401 surrounding the brake housing recess 410. The fixed annular gear is radially retained by a radially damping cylindrical damper 204. This damper is made of an elastomeric material, the cylindrical portion of which has a plurality of circumferential ribs which are compressed between the bore of the recess 410 and the surface of the skirt 213 of the fixed annular gear 21, providing sealing and radial damping.

[0102] At the front, the end of the damper 204 is extended radially inwards by an annular constriction inserted between the front end of the fixed annular gear 21 and the shoulder of the recess 410 of the caliper housing 41. Advantageously, this annular constriction has a concentric lip, here facing forward, which is compressed to facilitate sealing and axial damping.

[0103] At the rear, the end of the damper 204 is extended radially outwards by an annular flange inserted between the rear end of the sleeve 401 of the caliper housing 41 and the annular groove of the motor housing 10. Advantageously, this annular flange has a concentric lip, which here faces the rear and is compressed to facilitate sealing and axial damping.

[0104] In this way, the fixed ring gear 21 is retained within the motor unit by the motor housing 10 , and the damper 204 provides damping to prevent vibrations from being transmitted directly from the ring gear and possibly the motor housing 10 to the caliper housing 41 .

[0105] The movable ring gear 23 has a hole on the front side with longitudinal grooves 231. These longitudinal grooves 231 rotate the nut 31 of the screw-nut mechanism 3 through the longitudinal grooves 312 provided on the outer surface of the nut 31.

[0106] The nut 31 of the screw-nut mechanism is fixed against translation and is driven in rotation by the movable ring gear 23 and engages with the rotationally fixed screw 32 to cause said screw to translate.

[0107] Thus, the rotation of the nut 31 generates a linear drive of the screw 32 in a tightening direction F1 or in an opposite retraction direction, depending on the direction of rotation of the motor.

[0108] The nut 31 is guided in rotation by a rolling bearing 412 (in this case a roller bearing) mounted in a hole 410 of the caliper housing 41. The nut 31 cannot be axially translated in the tightening direction by the roller bearing 411 arranged between a shoulder facing forward of the caliper housing 41 and a bearing flange 311 around the nut 32, which abuts against an axial bearing surface of the shoulder.

[0109] The screw 32 of the screw-nut mechanism 3 is fixed to a support plate 33 acting as a brake piston, which transmits a linear actuation to at least one clamping pad 502 to generate a clamping force F1 on a disc 509 between the clamping pads 502 , 503 .

[0110] The input sun gear 32 has an axial recess 120 which is open at the front side and is designed to receive the screw 32 of the screw-nut mechanism 3 when in the retracted position (the position shown in the figure).

[0111] The support plate 33 here is basically disc-shaped and covers the engagement area between the screw and the nut, in a sense, the support plate 33 radially protrudes beyond the engagement area. Here, the support plate 33 is surrounded by a bellows seal 413.

[0112] In the tightening direction, the piston plate 32 is directly supported axially by the screw 32 of the screw-nut mechanism. The piston plate is attached to the end of the screw 32 (in this case the central screw 333) by an axial fastener, which provides traction on the plate when the screw moves in the retraction direction. The rotational attachment is ensured by the cooperation of the anti-rotation structure 323 carried by the end of the screw 32 and the complementary structure carried by the rear surface of the piston plate 33. The piston plate 33 is in turn held in rotation by anti-rotation recesses 335. These recesses are held fixed in a known manner against rotation by studs protruding from the rear surface of the internal clamping pad 502, which is in turn held in the bracket 501.

[0113] The above describes Figures 1 to 4This is an example of a preferred assembly method of the brake caliper 51, but this assembly can also be performed in different ways.

[0114] On the one hand, the shaft 13 of the hollow sun gear 12 is mounted coaxially with a bearing having one or more rolling bearings 14, in particular by means of a press fit, in a stator 111 of an electric motor 11 which also has an outer rotor 112. Figure 4 A motor unit 1 is shown.

[0115] On the other hand, the following components are inserted into the through recess 410 of the brake housing 41:

[0116] On the rear side, a movable ring gear 23; and

[0117] On the front side, the assembly including the screw-nut mechanism 3 is mounted by mounting the movable nut 31 of the screw-nut mechanism 3 in the brake housing recess 410. The rotatable nut is carried here by a bearing, which is guided in rotation by a roller bearing 412. The bearing also includes a roller bearing 411, which forms an axial stop to withstand the reaction force of the caliper housing 41 to the clamping force F1. In this example, the forward translation lock is achieved by a press fit between the roller bearing 411 and the hole of the brake housing recess 410.

[0118] The motor unit 1 (or the extended motor unit 1' defined below) is assembled here with the caliper housing 41 via the motor housing 10 and is attached in this case via an external elastic ring 105, which is installed between the movable parts of the differential reduction gear set 2, which have not yet been installed there.

[0119] Figure 2 A preferred but not mandatory example of internal element assembly is shown. Preferably, the fixed ring gear 21 is then fixed in the motor housing 10. Alternatively, the ring gear 21 is made by cutting its teeth directly into the material of its centering support 10.

[0120] The planetary gear 22 and its planetary carrier 220 are first inserted into the fixed annular gear to form Figure 2 The extended motor unit 1 'is shown, or alternatively, inserted into the movable ring gear 23. The movable ring gear 23 is inserted into the caliper housing 41 and here coupled with the screw-nut mechanism 3 by, for example, a circlip 302 inserted radially through a slot in the caliper housing 41, thereby forming an extended caliper housing 4'. The extended motor unit 1 'and the extended caliper housing 4' are then assembled together.

[0121] Second exemplary embodiment

[0122] Figures 5 to 8 A second example is shown, which will be described only for its differences.

[0123] In this example 52a, the motor 11 is also of the outer rotor type with an outer rotor 112 and an inner stator 111. Unlike the first disclosed example, this time the outer rotor is guided from the outside. This rotor is mounted in roller or needle bearings 15, which in turn are mounted in a bore of the motor housing 10. This feature is intended to be combined with the various variants of the rest of the actuator described herein.

[0124] Such external guidance is rarely used in this case, for example, because the position of the bearings inside the motor generally limits the linear movement speed of the bearing components relative to each other.

[0125] However, despite the additional radial space created by the outer bearing in this example, this arrangement offers new advantages, particularly for this type of actuator. In fact, when the screw 32 is retracted, the space released in the center of the motor extends the stroke of the screw 32 by extending the recess 120 formed in the center of the sun gear 12.

[0126] Furthermore, the option of guiding the rotor from the outside improves its centering accuracy relative to the centering support formed for it by the motor housing 10 and, therefore, also relative to the fixed annular gear 21 fixed to this motor housing. This improved centering reduces the manufacturing precision requirements and, for example, improves the acoustic and wear properties, in particular for such differential gearboxes with two different annular gears mounted on a common planetary gear.

[0127] This describes Figures 5 to 8 An example of a preferred assembly method of the brake caliper 51 will be described only according to its differences, but this assembly can also be performed in different ways.

[0128] In this example, the motor unit 1a is assembled by coaxially mounting the following components within a bore of a centering support (in this case the motor housing 10):

[0129] On the one hand, the outer rotor 112 of the electric motor 11 is coaxially installed in the hole of the centering support with the roller bearing or needle bearing 15, in particular, it is installed by press fitting. On the other hand, the fixed ring gear 21 of the differential planetary reduction gear set 2 is coaxially installed in the hole of the centering support, in particular, it is installed by press fitting of the ring gear insert 21.

[0130] Alternatively, the ring gear 21 is made by cutting the teeth directly into the material of its centering support 10 .

[0131] Therefore, if Figure 8 As shown, the motor unit 1 a further comprises a fixed ring gear 21 .

[0132] according to Figure 6 In the illustrated assembly example, the planetary gears 22 and their planet carrier 220 are first inserted into the fixed ring gear, forming the extended motor assembly 1 a ′.

[0133] According to the assembly example, the planetary gear and its planet carrier 220 are first inserted into the movable ring gear 23, as shown in FIG. Figure 8 As shown (or as Fig.10 , for the embodiments disclosed below).

[0134] In both cases, the movable ring gear 23 is inserted into the caliper housing 41 and there coupled with the screw-nut mechanism 3 by means of, for example, a circlip 302 inserted radially through a slot in the caliper housing 41 , thereby forming an extended caliper housing 4a ′.

[0135] Then, on the one hand, the motor unit 1a ( Figure 8 ) or extended motor unit 1a'( Figure 6 ) is assembled together with the expanded caliper housing 4a' on the other hand.

[0136] Third exemplary embodiment

[0137] Figures 9 to 11 A third example is shown, which will be described only in terms of its differences from the second example.

[0138] In this third example 52b, the motor is attached to the motor housing 10 via a common centering support 16 that forms a separate part from said housing 10. In this case, the centering support is a cylindrical tube, for example, made of a material and / or treated to make it more rigid than the rest of the motor housing 10. In this example, the fixed ring gear 21 is assembled and attached to the centering support 16 (as shown by the oval in the figure), for example by press fitting. Alternatively, it is also possible to cut the ring gear directly from the centering support material.

[0139] Of course, the invention is not limited to the examples described above and many modifications can be made to these examples without exceeding the scope of the invention.

[0140] Description of Reference Numerals

[0141] 1,1a Motor unit

[0142] 1',1a' Enlarged motor unit (with pre-installed planetary gear)

[0143] 10 Motor housing, the motor housing serves as a centering support

[0144] 101 Motor housing centering support for rotor bearing

[0145] 102 Motor housing skirt, centering support for fixed ring gear

[0146] 105 Mounting clip for mounting the motor housing on the caliper housing

[0147] 11 Motor

[0148] 110 Inner stator recess

[0149] 111 Stator

[0150] 112 Rotor

[0151] 117 Intermediate motor cover

[0152] 118 Circuit Board

[0153] 119 Radiator cap

[0154] 12 Hollow sun gear

[0155] 120 Sun gear recess

[0156] 13 Sun gear shaft

[0157] 14 Sun gear shaft rolling bearing

[0158] 15 External guide roller bearing of the rotor

[0159] 16 Common centering support for rotor and fixed ring gear

[0160] 162 A portion of a common centering support forming a fixed ring gear support

[0161] 191, 192 Motor electrical connector

[0162] 2 Epicyclic differential reduction gear set

[0163] 204 Cylindrical Damper

[0164] 21 Fixed ring gear

[0165] 211 Anti-rotation notch for fixed ring gear

[0166] 213 Skirt of fixed ring gear

[0167] 22 Planetary gear

[0168] 220 Planet carrier ring

[0169] 23 Movable ring gear

[0170] 231 Coupling spline of movable ring gear

[0171] 3 Screw-nut mechanism

[0172] 302 Removable ring gear assembly retaining ring with nut of screw-nut assembly

[0173] 31 Turn the nut

[0174] 311 Bearing flange of nut

[0175] 312 Nut coupling groove

[0176] 313 Ball bearings for screw-nut mechanisms

[0177] 32 Fixing screw to prevent rotation

[0178] 323 Rotational coupling structure of nut

[0179] 33 Support plate-brake piston

[0180] 333 Screws for attaching the support plate to the screws

[0181] 335 Anti-rotation notch in piston support plate

[0182] 4 Calipers

[0183] 4', 4a' Extended Caliper Housing (with screw-nut assembly pre-installed)

[0184] 401 Caliper housing rear sleeve

[0185] 41 Brake housing, caliper housing

[0186] 410 Caliper housing recess

[0187] 411 Axial stop with rolling bearing

[0188] 412 Guide bearing with rolling bearing

[0189] 413 Piston dust seal

[0190] 42 Caliper nose, outer caliper arm

[0191] 43 Screw for assembling the caliper nose to the caliper housing

[0192] 4',4a Extended Caliper Housing (with screw-nut assembly pre-installed)

[0193] 501 Bracket

[0194] 502 inner clamping pad

[0195] 503 External clamping pad

[0196] 509 Brake disc

[0197] 51 Brake (M1)

[0198] 52a Brake (M2)

[0199] 52b Brake (M3)

[0200] F1 Clamping force

Claims

1. A linear brake actuator (51, 52a, 52b) driven by an electric motor (11), in particular for road and / or motor vehicles, the actuator being mounted or intended to be mounted in a brake housing (41) having a through recess (410) between a front side facing the disc and a rear side opposite the front side, The actuator comprises a differential planetary reduction gear set (2) coaxial with the motor, the differential planetary reduction gear set (2) being driven by a sun gear (12) at the input end, the sun gear (12) driving a set of planetary gears (22), each of the planetary gears (22) being meshed with both a fixed annular gear (21) and a movable annular gear (23), the fixed annular gear (21) and the movable annular gear (23) having different numbers of teeth from each other, The movable ring gear (23) turns a reversible screw-nut mechanism (3) which produces a linear drive of the brake piston between a retracted position and an extended position, so as to apply linear pressure in a forward direction to generate a clamping force (F1) on the disc between the clamping pads (502, 503), It is irreversible at the differential planetary reduction gear set (2), that is, even if the screw-nut mechanism (3) itself does not exhibit such irreversibility, the linear force applied to the brake piston (33) in the release direction will be blocked by the actuator independently of the electric motor (11).

2. Linear brake actuator (51) according to the preceding claim, characterized in that The nut (31) of the screw-nut mechanism (3) is fixed to prevent translation and driven to rotate by the movable ring gear (23), and the nut (31) of the screw-nut mechanism (3) is engaged with the screw (32) fixed to prevent rotation so that the screw performs translational movement, thereby generating the linear drive, When in the retracted position, the screw (32) extends axially within a recess (120) provided in the input sun gear (12).

3. A linear brake actuator (51) according to any one of the preceding claims, characterized in that The actuator comprises a motor (11) of the type having an outer rotor (112) and an inner stator (111), And the input sun gear (12) is driven by the rotor (112) and carried by a shaft (13), which is guided in rotation by one or more rolling bearings (14) installed in the stator (111).

4. The linear brake actuator (52a, 52b) according to any one of claims 1 to 2, characterized in that: The actuator comprises a motor (11) of the type having an outer rotor (112) and an inner stator (111), The rotor (112) of the motor is guided in rotation in one or more rolling bearings (15) mounted in a bore of at least one centering support (101, 16) fixed to the fixed annular gear (21).

5. Linear brake actuator (52b) according to the preceding claim, characterized in that The screw (32) of the screw-nut mechanism (3) extends axially in a stator recess (110) provided in the stator (111).

6. The linear brake actuator (52a, 52b) according to any one of claims 4 to 5, characterized in that A single centering support (101, 16) made in one piece, for example of one material, carries or forms both the fixed ring gear (21) and the guide bearing (15) for the rotor (112).

7. Linear brake actuator (52b) according to the preceding claim, characterized in that The motor is attached to a housing, which can be the brake housing (41) or the motor housing (10), via a common centering support (16) forming a separate part from the housing.

8. A linear brake actuator (51, 52a, 52b) according to any one of the preceding claims, characterized in that The screw (32) is fixed to a support plate (33) which acts as a brake piston which transmits linear actuation to at least one clamping pad (502).

9. Linear brake actuator according to the preceding claim, characterized in that The nut (31) is arranged to be guided in rotation by one or more rolling bearings (412) mounted in a hole (410) in the brake housing (41); as well as The nut (31) is arranged to be guided in axial translation by at least one antifriction bearing (411) against an axial bearing surface of a shoulder of the brake housing facing forward, the at least one antifriction bearing being arranged between a front surface and a portion of the nut (32) extending radially to form a bearing flange (311).

10. The linear brake actuator (51) according to any one of claims 1 or 3, characterized in that: The motor has an inner stator and an outer rotor; and The input sun gear (12) is fixed to the rotor, the input sun gear (12) being carried by or integrated into a shaft (13) extending inside the stator (111), the shaft (13) being guided in rotation by an anti-friction bearing (14); and The movable ring gear (23) is guided to rotate by the inside of the fixed ring gear (21) or the centering support (10) of the fixed ring gear (21); and The movable ring gear (23) is rotationally attached to the nut (31) by engagement of longitudinal splines or teeth or grooves (231, 312); and The fixed ring gear (21) is mounted in or around a hole formed in a recess (410) in the brake housing (41), The nut (31) is mounted to rotate freely in a hole in a recess (410) of the brake housing (41), the hole terminating in a shoulder having a bearing surface facing forwards, against which the nut rests axially; and The screw (32) is fixed to a support plate (33), which forms a brake piston and keeps the screw (32) fixed and non-rotatable, in particular by rotationally coupling the piston (33) with a brake pad (502) that receives the linear force (F1) of the piston (33) (33, 323) and the brake pad (502) itself being held non-rotatable by a fixed bracket (501).

11. The linear brake actuator (52a, 52b) according to any one of claims 1 or 4 to 6, characterized in that The motor (11) has an inner stator (111) and an outer rotor (112); and the rotor (111) is guided in rotation by an outer bearing (15) mounted in a centering element (10, 16), and the rotor is rotationally fixed to the input sun gear (12); and The stator (11) is hollow, that is, the stator has an axial recess (110) over at least half the length of the motor (11), and the axial recess is designed to allow the screw (32) to pass through the input sun gear (12) and the stator (111); The fixed annular gear (21) is mounted on or integrated into a centering support (10, 16) which receives at least one of the motor rolling bearings (15) or forms part of the motor rolling bearing, i.e. the centering support (10, 16) is made of a single material or has material continuity between the part (101) forming or receiving the motor bearing (15) and the part (102, 162) forming or receiving the fixed annular gear (21); and The movable annular gear (23) is guided in rotation in the fixed annular gear (21) or in a centering support (10, 16) of the fixed annular gear (21); and The movable ring gear (23) is rotationally fixed to the nut (31) by engagement of longitudinal splines or teeth or grooves (231, 312); and The fixed ring gear (21) or the centering support (10, 16) of the fixed ring gear (21) is mounted in or around a recess (410) arranged in the brake housing (41), The nut (31) is mounted to rotate freely in a hole in a recess (410) of the brake housing (41), the hole terminating in a shoulder having a bearing surface facing forwards, against which the nut rests axially; and The screw (32) is fixed (33, 323) to a support plate (33), which forms a brake piston and keeps the screw (32) fixed and non-rotatable, in particular by rotationally coupling (335) the piston (33) with a brake pad (502) that receives the linear force (F1) of the piston and the brake pad (502) itself is held non-rotatable by a fixed bracket (501).

12. A linear brake actuator according to any one of the preceding claims, characterised in that The movable annular gear (23) is rotatable within the fixed annular gear (21) or within a centering support (10, 16) of the fixed annular gear (21).

13. A linear brake actuator according to any one of the preceding claims, characterised in that The fixed annular gear (21) is arranged in a bore of a brake housing recess (410), the fixed annular gear (21) being radially retained in the bore by at least one cylindrical damper (204) having at least radial damping, the damper being in particular formed completely or partly from an elastomeric material, The cylindrical damper (204) is compressed, for example, between the brake housing (41) and a skirt fixed to the fixed ring gear (21), for example, extending towards and around the movable ring gear (23).

14. A linear brake actuator according to any one of the preceding claims, characterised in that The screw is linearly supported in a coaxial hydraulic piston which forms a selectively electrically and / or hydraulically actuated brake piston.

15. A disc brake with a floating or sliding caliper (51, 52a, 52b), in particular for road and / or motor vehicles, the brake comprising a caliper (4) forming two arms intended to span over at least one brake disc in order to apply a braking torque thereto by clamping at least two brake pads (502, 503) on the two faces of the brake disc, at least one of the two arms comprising a body forming a caliper housing (41), the body forming the brake housing, the brake housing receiving a linear actuation mechanism arranged to produce the clamping by linearly moving at least one brake piston (33) pressing against at least one clamping pad (502), It is characterized in that The linear actuation mechanism comprises at least one electric actuator according to any one of claims 1-13, which is arranged to generate linear clamping and loosening or tensioning forces at the rear of a support plate forming a brake piston (33), without hydraulic actuation of the brake piston (33).

16. A disc brake with a floating or sliding caliper, in particular for road and / or motor vehicles, said brake comprising a caliper forming two arms intended to straddle at least one brake disc in order to apply a braking torque thereto by clamping at least two brake pads on the two faces of said disc, at least one of said two arms comprising a body forming a brake housing receiving a linear actuation mechanism arranged to produce said clamping by linearly moving at least one brake piston pressing on at least one clamping pad, It is characterized in that The linear actuation mechanism comprises at least one linear brake actuator according to any one of claims 1 to 14, arranged to generate a linear clamping force in a hydraulic piston accommodated in a hydraulic chamber controlled by a hydraulic circuit.

17. A vehicle or a vehicle subassembly, in particular for road and / or automotive use, comprising a brake according to any one of claims 15-16 or a brake comprising an actuator according to any one of claims 1-14.

18. A method for manufacturing a brake actuator (51) according to any one of claims 1 to 14, or a brake (51) according to any one of claims 15 to 16, or a vehicle or a subassembly according to claim 17, in combination with claim 2, characterized in that The method comprises: On the one hand, a shaft (13) of a hollow sun gear (12) is coaxially mounted with a bearing having one or more rolling bearings (14) in a stator (111) of an electric motor (11) having an outer rotor (112), in particular by means of a press fit, so that a motor unit (1) is formed, or such a motor unit is provided; In another aspect, the method comprises the following steps: Inserting the movable ring gear (23) into the rear side of the brake housing (41); and inserting the assembly including the screw-nut mechanism (3) into the front side of the brake housing (41) by mounting the movable nut (31) of the screw-nut mechanism (3) in a brake housing recess (410) by means of at least one bearing, wherein the at least one bearing guides the movable nut to rotate by means of a rolling bearing (412) and guides the movable nut to abut axially backward by means of a rolling bearing (411); During or after insertion, a rotational coupling (231-312) and preferably also a translational coupling is effected between the movable ring gear (23) and the movable nut (31).

19. A method for manufacturing a brake actuator (52a, 52b) according to any one of claims 1 to 14, or a brake (52a, 52b) according to any one of claims 15 to 16, in combination with claim 4, characterized in that: The method comprises: On the one hand, a motor unit (1a) is assembled in the following manner, or a motor unit assembled in this manner is provided: On the one hand, the outer rotor (112) of the electric motor (11) is coaxially mounted with a bearing having one or more rolling bearings (15) in the centering support (10, 16), in particular by means of a press fit; on the other hand, the fixed ring gear (21) of the differential planetary reduction gear set (2) is coaxially mounted in a rotationally fixed manner in the centering support (10, 16), in particular by means of a press fit of a ring gear insert (21) or by cutting the teeth of the ring gear directly into the material of the support element (10, 16); In another aspect, the method comprises the following steps: Inserting the movable ring gear (23) into the rear side of the brake housing (41); and inserting the assembly including the screw-nut mechanism (3) into the front side of the brake housing (41) by mounting the movable nut (31) of the screw-nut mechanism (3) in a brake housing recess (410) by means of at least one bearing, wherein the at least one bearing guides the movable nut to rotate relative to the brake housing by means of a rolling bearing (412) and guides the movable nut to abut axially backward by means of a rolling bearing (411); During or after insertion, a rotational coupling (231-312) and preferably also a translational coupling is effected between the movable ring gear (23) and the movable nut (31).

Images