FR3135495A1 - “Electric brake actuator, brake and assembly method, in particular for all-electric disc brake” - Google Patents

Abstract

The invention relates to an electric brake actuator. A motor (11) drives at the end the input planetary pinion (12) of a differential planetary gearbox whose satellites (22) mesh with a fixed ring gear (21) and a mobile ring gear (23). This reducer thus provides irreversibility and is combined in series with a reversible screw-nut mechanism (31-32). Advantageously, the movable crown rotates the nut, which translates (F1) the screw fixed in rotation. The input pinion advantageously has an axial housing (120) receiving the screw when it retracts. The motor has an outer rotor mounted in an outer bearing (15), the screw housing (120) extending axially inside the stator (111). A common centering support (16) carries the motor bearing and the fixed ring gear. The mobile crown and the screw-nut (3) are assembled on either side of a housing (410) passing through the caliper. Figure for the abstract: Fig.1

Description

“Electric brake actuator, brake and assembly method, in particular for all-electric disc brake”

The invention relates to an electric brake actuator, in particular for a disc brake and in particular a sliding caliper, in particular for all-electric operation. A motor drives the input planetary pinion at the end of a differential planetary gearbox whose satellites mesh with a fixed ring gear and a mobile ring gear. This reducer thus provides irreversibility and is combined in series with a reversible screw-nut mechanism.

Advantageously, the movable crown rotates the fixed nut in translation, which translates the screw fixed in rotation by the piston and the linings. The input planetary pinion advantageously has an axial housing receiving the screw when it retracts. Preferably the motor has an outer rotor mounted in an outer bearing, the screw housing extending axially inside the stator. A common centering support, in particular attached, carries the motor bearing and the fixed crown. The movable crown and the screw-nut mechanism are assembled on either side of a housing passing through the caliper and coupled in rotation inside said housing, which receives the motor unit on its rear opening.

The invention further relates to a disc brake comprising such an actuator, in particular for producing a parking brake, as well as a method of assembling such a brake.

State of the art

A “coaxial geared motor” architecture was proposed previously, by document US4804073. This document proposes a "differential" gearbox, in which two epicyclic gear trains share the same group of "common" satellites which all mesh on two different ring gears, one fixed and one mobile. These satellites are driven at the input by a sun gear and the two crowns have different numbers of teeth from each other, the mobile crown is thus driven to form an output with a very high reduction. It rotates a screw located in the piston, which moves in translation a fixed nut in rotation, which moves the piston in translation.

This architecture, however, presents a significant axial bulk, which makes its integration into a vehicle difficult.

More recently, document FR3031154 proposes another "coaxial" architecture, equipped with an upstream epicyclic stage which uses the same fixed ring gear as the first train of the differential gearbox. In this structure, these three epicyclic trains are housed inside the piston, the movable crown forming the screw which translates the nut of the screw-nut mechanism, this nut being formed by the brake piston itself.

This solution, however, still presents a certain axial bulk, and can pose significant difficulties and constraints, for example in terms of industrialization or effort capacity.

Another arrangement, with a “lateral gear motor”, is known from document FR2999257A1. In this gear motor, the motor axis is parallel and laterally offset from the output of the gearbox.

In this configuration, the brake piston is actuated linearly ("forward" for tightening) by a fixed rotating nut, itself moved by the rotation of a screw placed inside the piston. This screw is driven in from the “rear” of the brake, by the gear motor. This is equipped with a motor and an epicyclic reduction gear coaxial with each other, with an axis offset from the axis of the screw, and whose outputs are directed “towards the rear”.

This architecture is currently implemented on various vehicles, but nevertheless presents a significant footprint, particularly on the side.

One aim of the invention is to overcome, in whole or in part, the disadvantages of the state of the art. It is sought in particular to improve compactness, to simplify integration into different types of vehicle, to make manufacturing simpler and less expensive, and/or to optimize the compromises between these factors. These goals are sought through the different constituents and processes used and taking into account the constraints which prevail in the field of motors and actuators and in particular for automobiles and their braking; 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 sound operation.

Presentation of the invention

For this, the invention proposes a linear brake actuator, in particular a disc, driven by an electric motor, in particular for road vehicles and/or automobiles. This actuator is mounted or intended to be mounted in a brake housing, in particular a caliper housing, which has a through housing between a front side directed towards the disc and a rear side opposite the front side.

According to the invention, this actuator comprises a differential planetary gearbox coaxial with the motor, which gearbox is driven at the input by a planetary pinion, which drives a group of satellites which each mesh with both a fixed ring gear and a mobile ring gear, which crowns carry different numbers of teeth from each other.

The mobile crown rotates a reversible screw-nut mechanism which produces a linear drive of a brake piston between a retracted position and an extended position, so as to exert linear support in a so-called forward direction to produce a clamping force on a disc between clamping pads, in an irreversible manner at the level of the differential planetary gearbox, in the sense that a linear force exerted on the brake piston in the direction of release will be blocked by said actuator, independently of the electric motor and even if the screw-nut mechanism does not itself present such irreversibility.

Indeed, although the basic principle of this kinematics is reversible according to a purely theoretical approach, the inventors have noted that this kinematics can in reality present an operation of an irreversible nature, at least in conditions where it is arranged to obtain the size and reduction suitable for use in such a brake actuator.

This irreversibility is obtained in particular for reduction ratios greater than 20, and in particular greater than or equal to 28 or even 30. Ratios have been experimented with values of 28, 30, 36, 54.2, 60, as well as 88.

It is thus possible to produce an irreversible brake actuator while providing a reversible screw-nut mechanism in itself, and therefore with better efficiency than for a non-reversible screw-nut. This makes it possible, for example, to produce a reliable electric parking brake with zero consumption when parked, but which has good energy efficiency when actuated. For example, we save energy, but we also improve the size and/or reliability since the better efficiency allows for example the choice of a less powerful motor and/or provides better reliability.

For example, such a differential planetary gearbox allows an energy efficiency of around 50% to 70%. It is here combined in series with a reversible screw-nut whose efficiency is of the order of 85% to 90%. We then obtain an overall yield greater than 42%.

We thus obtain an overall energy efficiency much higher than the combination of the state of the art based on an irreversible screw-nut with an efficiency less than 35% associated with a conventional epicyclic gear train whose gears give an efficiency of the order of 90%, which gives an overall yield of less than 31%.

Preferably, the movable crown and the fixed crown have a difference between them of at least three teeth, or even of at least five teeth. Preferably, this difference is at most seven teeth, or even at most five teeth. Typically, this difference in number of teeth is a multiple of the number of satellites.

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 in translation and is driven in rotation by the movable crown, and cooperates with a fixed screw in rotation to move said screw in translation and thus produce said linear drive. This screw extends axially inside a housing provided inside said input planetary pinion when it is in the retracted position.

We thus obtain better axial compactness, and also the possibility of making a longer screw for the same external axial size. This makes it possible, for example, to obtain a better compromise between axial compactness, stroke length, and guiding precision.

For example, for the same axial dimensions, this screw architecture passing through the hollow sun gear allows you to go from a stroke of 18mm to a stroke of 43mm; i.e. an additional stroke of 25mm, or 5 more turns if the pitch is 5mm. This gives for example a greater margin to compensate for the wear of the linings, and allows for example to use thicker linings; and/or to reduce the axial bulk of the actuator and the brake.

According to a first particular family of embodiments, this linear brake actuator comprises a motor of a type with an external rotor and internal stator, called "out-runner" in English vocabulary, for example whose stator is fixed to the inside a motor housing by a transverse end flange. In addition, the input planetary pinion is driven by the rotor and is carried by a shaft which is guided in rotation by one or more bearings mounted inside the stator.

We thus obtain a simple and robust architecture.

According to a preferred example of embodiment within this first family:

the motor has an inner stator and an outer rotor; And

the input planetary pinion is integral with the rotor and is carried by or integrated into a shaft which extends inside the stator where it is guided in rotation by a rolling bearing; And

the movable crown is preferably movable in rotation inside the fixed crown or its centering support; And

the movable crown is secured to the nut in rotation by cooperation of splines or teeth or longitudinal grooves (strictly longitudinal, or less than 20° or even less than 10°); And

the fixed crown is fitted in or around a housing provided in the brake housing or a housing attached to it,

the nut is mounted to rotate freely in a bore of the brake housing, which ends in a shoulder having a bearing face directed towards the front and on which the nut comes into axial abutment; And

the screw is integral with a support plate forming a brake piston and which keeps said fixed screw in rotation, in particular by rotating coupling of said piston with a braking pad which receives its linear force and is itself kept in rotation by a fixed screed.

According to a second particular family of embodiments, this linear brake actuator comprises a motor of a type with external rotor and internal stator, and its rotor is guided in rotation inside one or more bearings mounted in a bore at least one centering support, which is integral with the fixed crown (in any way, for example in a single piece or in assembled form).

We thus obtain better compactness, and/or better centering of the motor and/or of the different elements of the kinematic chain, for example between the rotor of the motor and the planetary input pinion of the differential gearbox.

According to an advantageous but optional characteristic, the screw of the screw-nut mechanism extends axially inside a stator housing provided inside the stator. It is thus possible to further improve the axial compactness and/or the length of the screw and therefore the stroke. According to a preferred example of embodiment within this second family:

the motor has an inner stator and an outer rotor; And

said rotor is guided in rotation by an external bearing mounted inside a centering element, and is integral in rotation with the input planetary pinion, and preferably also in translation; And

said stator is hollow in the sense that it has, over at least half the length of the motor, and preferably the entire length, an axial housing arranged to allow the passage of the screw inside the input planetary pinion and said stator;

the fixed crown is mounted on or integrated into a centering support which receives at least one of the motor bearings or forms a part of said motor bearing, that is to say that this centering support is made of a single material or with continuity of material between a part forming or receiving said motor bearing and a part forming or receiving the fixed crown; And

the movable crown is secured to the nut in rotation by cooperation of splines or teeth or longitudinal grooves (strictly or at less than 20° or even less than 10°); And

the fixed crown or its centering support is fitted in or around a housing provided in the brake housing,

the nut is mounted to rotate freely in a bore of the brake housing, which ends in a shoulder having a bearing face directed towards the front and on which the nut comes into axial abutment; And

the screw is integral with a support plate forming a brake piston and which keeps said fixed screw in rotation, in particular by rotating coupling of said piston with a braking pad which receives its linear force and is itself kept in rotation by a fixed screed.

According to another optional advantageous characteristic, possibly combined with the previous ones but not necessarily, the same centering support, made in a single piece (that is to say with continuity of material, for example by overmolding or welding) and in particular in a single material ( for example by molding, or machining a single initial block of material), carries and/or forms both the fixed crown and a guide bearing for the rotor.

Advantageously, the motor is fixed to a housing via a common centering support, in particular made of plastic or aluminum alloy. This housing is typically a motor housing which is assembled on the brake housing, or directly the brake housing itself.

It is thus easier to obtain a high-performance centering support while optimizing manufacturing constraints and allowing range modularity which simplifies the design and manufacturing or maintenance process.

According to yet another optional advantageous characteristic, possibly combined with the previous ones but not necessarily, the screw is integral with a support plate playing the role of a brake piston which transmits the linear actuation to at least one clamping pad . Typically, the support plate covers the zone of cooperation between the screw and the nut, in the sense that it projects radially outside this zone of cooperation.

More particularly, the nut is arranged to be guided:

in rotation, by one or more bearings, in particular roller or needle bearings, mounted inside a bore formed in the caliper housing; And

in axial translation, by abutment against an axial bearing face of a shoulder of the caliper housing directed towards the front side, via at least one bearing with rollers, in particular rollers or needles, disposed between said face front and a part of the nut extending radially to form a support collar.

According to different particularities, intended to be combined together or not and with all or part of the optional characteristics exposed here:

the fixed crown is integral with a skirt which extends towards and around the movable crown;

the differential gearbox is mounted in a housing formed in the brake housing, in particular opening towards the rear to allow mounting of said gearbox from the rear of said housing;

the motor is mounted in an external housing, which is fitted into or around the brake housing, in particular so as to close the housing of the brake housing which contains the reducer;

the movable crown is guided in rotation by the inside of the fixed crown or its centering support;

the fixed crown is arranged in a bore of the brake housing housing, where it is held radially by means of at least one cylindrical shock absorber with at least radial damping, in particular formed entirely or partly of an elastomeric material, said cylindrical shock absorber being for example compressed between the brake housing and a skirt secured to the fixed crown, which skirt extends for example towards and around the movable crown.

The actuator as explained here makes it possible to produce an all-electric brake, that is to say not requiring or even including hydraulic operation, for the function of service brake or emergency brake or emergency brake. parking or any of the possible combinations of these functions.

However, such an actuator is also provided in a version where the screw comes into linear support inside a hydraulic piston which is coaxial with it, which creates a brake piston with selectively electric and/or hydraulic actuation.

According to another aspect of the invention, a brake is proposed comprising an actuator as explained here, in particular for a road vehicle and/or automobile, as well as a vehicle comprising such a brake. Such a brake is envisaged in all the different types of architecture currently known, for example a disc brake, or a disc brake incorporated inside a drum brake giving an assembly called "drum-in-hat" in Anglo-Saxon vocabulary.

According to an advantageous feature, a disc brake of fixed or sliding or floating caliper type is proposed in all its different versions currently known. This actuator is in fact particularly well suited to integration into a disc brake, for example from the point of view of size and/or stroke and speed effort capacities, typically in the body or caliper housing, which achieves then the "brake housing" of this actuator.

According to an advantageous feature, this disc brake is of the floating or sliding caliper type, comprising a caliper forming two branches intended to span at least one brake disc to apply a braking torque to it by tightening at least two braking pads on both sides of this disc. At least one of these branches comprises a body forming a caliper housing, producing the brake housing of the actuator. This caliper housing receives a linear actuation mechanism arranged to produce this tightening by linearly moving at least one brake piston which presses on at least one clamping pad. According to this particularity, this linear actuation mechanism comprises at least one electric actuator as explained here, which is arranged to produce a tightening and loosening force supporting or linear traction at the rear of a support plate forming a brake piston devoid of hydraulic actuation (and in particular devoid of hydraulic actuation chamber).

Alternatively, this disc brake disc brake is of the floating or sliding caliper type, comprising a caliper forming two branches intended to span at least one brake disc to apply a braking torque to it by tightening at least two braking pads on both sides of this disc. At least one of these branches comprises a body forming a brake housing receiving a linear actuation mechanism arranged to produce this tightening by linearly moving at least one brake piston which presses on at least one clamping pad. This linear actuation mechanism then comprises at least one electric actuator as explained here, which is arranged to produce a tightening force by linear support inside a hydraulic piston housed in a hydraulic chamber which is controlled by a hydraulic circuit. For example, the hydraulic chamber is arranged around or in the axial extension of the bore receiving the nut.

According to yet another aspect, the invention proposes a method of manufacturing a brake actuator as explained here, or a brake comprising such an actuator, or a vehicle or vehicle subassembly comprising such a brake.

According to a particular feature, applied to the case of an actuator with a hollow planetary pinion, this method advantageously comprises:

on the one hand a coaxial mounting of a hollow planetary pinion shaft inside the stator of an electric motor with an external rotor, with a bearing with one or more bearings, in particular by a tight fitting, thus forming a motor group , or supply of such a power unit;

on the other hand the following steps:

insertion inside the brake housing: on the rear side of the movable crown; and on the front side of an assembly comprising the screw-nut mechanism. The latter is inserted by mounting its movable nut in the brake housing housing by means of at least one bearing guiding said movable nut in rotation by rolling and in axial abutment towards the rear by rolling. For example, translational support in both directions is obtained by tight fitting between the bearing and the brake housing housing;

rotational coupling between the movable crown and the movable nut (around the screw and inside the brake housing), during insertion or subsequently, in particular by engagement of longitudinal grooves, and preferably also in translation in particular by a circlip.

More particularly, in the case of an actuator with a common centering support (or even separate from the housing), this method advantageously comprises:

on the one hand an assembly of a motor group, or a supply of a motor group thus assembled, by coaxial mounting inside the centering support: on the one hand, of the outer rotor of the electric motor, with a bearing with one or more bearings, in particular by a tight fitting, and on the other hand, integrally in rotation, with the fixed crown of the differential planetary gearbox, in particular by tight fitting of an attached crown or by direct cutting of the teeth of said crown in the material of the support element;

on the other hand the following steps:

insertion inside the brake housing: on the rear side of the movable crown; and on the front side of an assembly comprising the screw-nut mechanism. The latter is inserted by mounting its movable nut in the brake housing housing by means of at least one bearing guiding said movable nut in rotation by rolling and in axial abutment towards the rear by rolling. For example, translational support in both directions is obtained by tight fitting between the bearing and the brake housing housing;

rotational coupling between the movable crown and the movable nut (around the screw and inside the brake housing), during insertion or subsequently, in particular by engagement of longitudinal grooves, and preferably also in translation in particular by a circlip.

Various embodiments of the invention are planned, integrating according to all of their possible combinations the different optional characteristics exposed here.

Other particularities and advantages of the invention will emerge from the detailed description of a mode of implementation in no way limiting, and from the appended drawings in which:

: there is a longitudinal section diagram which illustrates an actuator, according to a first exemplary embodiment with the input pinion on a motor shaft mounted in the stator;

: there is a top view diagram that illustrates the assembly of the actuator of the ;

: there is a scale view in longitudinal section which illustrates an all-electric disc brake in an exemplary embodiment including the actuator of the ;

: there is an exploded view in perspective and to scale which illustrates an example of assembly of the actuator of the ;

: there is a longitudinal section diagram which illustrates an actuator, according to a second exemplary embodiment the rotor mounted on an external bearing;

: there is a top view diagram that illustrates the assembly of the actuator of the ;

: there is a scale view in longitudinal section which illustrates an all-electric disc brake in an exemplary embodiment including the actuator of the ;

: there is an exploded view in perspective and to scale which illustrates an example of assembly of the actuator of the ;

: there is a longitudinal section diagram which illustrates an actuator, according to a variant of the second exemplary embodiment, with the rotor bearing and the fixed crown mounted on the same tube, forming a common centering element which is assembled with the motor housing ;

: there is a top view diagram that illustrates the assembly of the actuator of the ;

: there is a scale view in longitudinal section which illustrates an all-electric disc brake in an exemplary embodiment including the actuator of the ;

: there is a scale perspective view which illustrates an example of a disc brake according to an exemplary embodiment including the actuator of the Or Or ;

: there is a scale perspective view which illustrates from a different angle certain sub-assemblies of the brake of the : reference 13a concerns the differential gearbox with its fixed crown, reference 13b concerns the differential gearbox without its fixed crown, reference 13c concerns the screw-nut mechanism, and reference 13d concerns the caliper nose in the form of an attached part .

Description of exemplary embodiments

THE has illustrate examples of embodiments of the invention, in which the electric actuator uses a differential epicyclic gearbox 2, which drives a screw-nut mechanism 3 of the reversible type. This reversible screw-nut mechanism is here produced in the form of a ball screw 32 in the thread of which balls 313 circulate which ensure its cooperation with a nut 31.

This choice of a reversible screw-nut allows good energy efficiency and greater freedom of choice of pitch than when an irreversible screw-nut is imposed (as is the case in a number of known achievements for electric parking brakes). This choice is made possible by the irreversibility of the differential epicyclic gearbox used.

In the present examples, the screw-nut mechanism 3 is rotated by its nut 31, to move it in translation while maintaining the screw 32 stationary in rotation. However, the opposite is also provided, with a differential epicyclic gearbox driving a known screw-nut mechanism in which the screw is driven in rotation and fixed in translation while the nut is kept stationary in rotation and movable in translation.

First example of embodiment

In has an actuator according to a first exemplary embodiment is illustrated, implemented in the case of a disc brake with a sliding caliper.

As seen in the overviews of And , the actuator of the is mounted in the body 41 of the caliper 4 of a disc brake 51, and on only one side of the disc 509. In tightening mode, this actuator applies a linear force F1 on an internal clamping pad 502, which presses on the interior friction track of the disc 509, which rests in reaction on an exterior clamping pad 503, which itself rests on the "nose" of the exterior branch 42 of the caliper.

These clamping pads 502, 503 are guided in translation, and held in rotation to transmit the braking torque, by the yoke 501 or "bracket" in English vocabulary, which is fixed to the suspended part of the running gear. In known manner, the stirrup 4 itself is mounted on the yoke 501 by columns 504, which keep it immobile in rotation and free in translation, which allows it to move to distribute the clamping force on the two faces of the disc, thus forming a “sliding yoke” architecture.

In this example, as shown in and especially in , And , the caliper is itself made in the form of two different parts: a caliper body or caliper housing 41 and an attached nose 42, which are assembled together integrally by screws 43, which facilitates for example the assembly of the actuator. However, this configuration is also intended to be implemented with a stirrup made in a single piece.

The motor 1 comprises a stator 111 which is fixed by pinching between a shoulder of the motor housing 10 and a shoulder of an intermediate cover 117, which also carries an electronic card 118 which controls the motor and integrates power electronics supplying the windings. This intermediate cover 117 is closed at its rear end by a cover 119 forming a thermal radiator with the outside air, to evacuate the heat emitted by the electronic card 118 through fins. This radiator cover 119, for example made of cast aluminum alloy for example by pressure injection, is in contact with the hot components of the electronic card 118, typically via a thermally conductive paste.

In this example, the motor 1 is of the type with an internal stator 111 and an external rotor 112, here as an example a direct current motor with permanent magnets in the stator and magnetic windings in the stator. However, other types of known motors are also provided, for example a conventional type with internal rotor and external stator.

The rotor 112 is integral with an input planetary pinion 12, which comprises a shaft 13 which is guided in rotation by the bearings 14 mounted inside the tubular part of the stator 111.

The fixed crown 21 is fixed to the motor housing 10, here by fitting inside a skirt 102 projecting axially from the motor housing on the front side. In this example, the fitting is tight and the anti-rotation is achieved by cooperation of shapes, here axial protrusions 211 which protrude from the fixed crown and cooperate with voids formed in the skirt 102. Once the assembly is assembled, the fixed crown 21 is fitted into a bore at the entrance to the brake housing housing 410.

The input planetary pinion 12 meshes with a group of satellites 22, which are held in cages of a planet carrier ring 220.

These satellites 22 have a sufficient length to each mesh both with the fixed crown 21 and with a movable crown 23 which is coaxial and axially offset relative to said fixed crown. In this example, the fixed crown 21 and the movable crown 23 have the same internal diameter and both have a module compatible with the toothing of the satellites, which is identical over the entire length of said satellites.

In this example, the movable crown 23 is guided in rotation, for example by lubricated friction, inside a skirt 213 which protrudes axially from the fixed crown 21 and is coaxial with it.

The movable crown 23 has a number of teeth which differs from the fixed crown 21, by a small number of teeth, for example from 4 to 5. It meshes with the satellites 22 which are supported on the fixed crown 21, here with the same toothing, so that the mobile crown 23 is rotated by said satellites with a very reduced speed compared to the speed of the input planetary pinion 12.

In this example, advantageously but optionally, the motor 11 is fixed in motor housing 10, which is distinct from the bracket 41. The motor housing 10 has an axial skirt 104 which extends towards the front side, and is fits around a part of the brake housing 41 forming a sleeve 401 extending from the rear side. This interlocking between skirt 104 and sleeve 401 maintains the motor housing 10 on the stirrup housing 41, here with engagement of anti-rotation shapes and retained in translation by an external circlip 105.

Advantageously but optionally, the fixed crown 21 is arranged in a bore inside the sleeve 401 which surrounds the brake housing housing 410. The fixed crown is held there radially by means of a cylindrical damper 204 at radial damping. This shock absorber is here formed by an elastomeric material, the cylindrical part of which carries a plurality of circumferential ribs, which are compressed between the bore of the housing 410 and the surface of the skirt 213 of the fixed crown 21, ensuring sealing and radial damping.

On the front side, the end of the shock absorber 204 extends radially inwards by an annular constriction which is interposed between the front end of the fixed crown 21 and a shoulder of the housing 410 of the caliper housing 41 Advantageously, this annular constriction has concentric lips, here towards the front, which are compressed to contribute to sealing and axial damping.

On the rear side, the end of the shock absorber 204 extends radially outwards by an annular flange which is interposed between the rear end of the sleeve 401 of the caliper housing 41 and an annular groove of the motor housing 10 Advantageously, this annular collar has concentric lips, here towards the rear, which are compressed to contribute to sealing and axial damping.

Thus, the fixed crown 21 is held within the motor group by the motor housing 10, and the shock absorber 204 provides damping to avoid the direct transmission of vibrations from the crown and possibly the motor housing 10 to the caliper housing 41 .

The movable crown 23 has a bore on the front side which carries longitudinal grooves 231. They cause the nut 31 of the screw-nut mechanism 3 to rotate through longitudinal grooves 312 which this nut 31 carries on its exterior surface.

The nut 31 of the screw-nut mechanism is fixed in translation and is rotated by the movable crown 23, and cooperates with the screw 32 fixed in rotation to move said screw in translation.

The rotation of the nut 31 thus produces a linear drive of the screw 32, in the direction of tightening F1 or in the opposite direction of withdrawal depending on the direction of rotation of the motor.

The nut 31 is guided in rotation by a bearing 412, here roller bearing, mounted inside a bore 410 provided in the stirrup housing 41. It is immobilized in axial translation, in the direction of tightening, by abutment against an axial bearing face of a shoulder of the caliper housing 41 directed towards the front side, via a roller bearing 411 disposed between this shoulder and a support collar 311 which surrounds the nut 32.

This screw 32 of the screw-nut mechanism 3 is integral with a support plate 33 playing the role of a brake piston, which transmits the linear actuation to at least one clamping pad 502, to produce a clamping force F1 on the disk 509 between clamping pads 502, 503.

The input planetary pinion 32 has an axial housing 120 which opens from the front side, and is designed to be able to receive the screw 32 of the screw-nut mechanism 3 when it is in the retracted position (position illustrated in the figure).

The support plate 33 here has substantially the shape of a disc, and it covers the zone of cooperation between the screw and the nut, in the sense that it protrudes radially from it. It is here surrounded by a bellows seal 413.

In the tightening direction, the piston plate 32 directly receives the axial support of the screw 32 of the screw-nut mechanism. It is fixed to the end of the screw 32 by an axial fixing means, here a central screw 333, which provides traction on the plate when the screw moves in the direction of withdrawal. Rotational fixation is ensured by cooperation of an anti-rotation shape 323 carried by the end of the screw 32 with a complementary shape carried by the rear face of the piston plate 33. This is itself kept in rotation by anti-rotation notches 335. These are kept fixed in rotation in a known manner by studs projecting from the rear face of the internal clamping pad 502, itself held inside the yoke 501.

An example of a preferred assembly method is described here for the brake caliper 51 of the has , but this assembly can also be carried out differently.

On the one hand, the coaxial assembly of the shaft 13 of the hollow planetary pinion 12 is carried out inside the stator 111 of the electric motor 11 with external rotor 112, here with a bearing with one or more bearings 14, in particular by a tight fitting. We thus obtain a motor group 1, illustrated in .

On the other hand, we insert inside the through housing 410 of the brake housing 41:

on the rear side the movable crown 23; And

on the front side an assembly comprising the screw-nut mechanism 3, by mounting its movable nut 31 in the housing 410 of the brake housing. This nut movable in rotation is here carried by a bearing providing guidance in rotation by a roller bearing 412. This bearing also includes a roller thrust bearing 411 forming an axial thrust bearing to support the reaction of the stirrup housing 41 to the force tightening F1. In this example, blocking in forward translation is achieved by tight fitting between the roller bearing 411 and the bore of the brake housing housing 410.

The motor unit 1 (or the enlarged motor unit 1' defined below) is assembled with the caliper housing 41, here by its motor housing 10, and fixed in this example by an external circlip 105; by mounting between them the mobile elements of the differential gearbox 2 which are not already there.

There illustrates a preferred but not obligatory example of the assembly of interior elements. Preferably, the fixed crown 21 is then fixed in the motor housing 10. Alternatively, the crown 21 is produced by direct cutting of its teeth in the material of its centering support 10.

The satellites 22 and their planet carrier 220 are inserted first into the fixed ring, forming the enlarged motor group 1' of the , or alternatively in the movable crown 23. The movable crown 23 is inserted in the caliper housing 41 and coupled with the screw-nut mechanism 3, here by a circlip 302 inserted for example radially through slots in the caliper housing 41 , thus forming the enlarged stirrup housing 4'. The enlarged motor unit 1' and the enlarged caliper housing 4' are then assembled together.

Second example embodiment

THE has illustrate a second example of an embodiment, which will only be described in its differences.

In this example 52a, the motor 11 is also of a type with an external rotor 112 and an internal stator 111. Unlike the first example described, the external rotor is this time guided from the outside. It is mounted inside a roller or needle bearing 15, which is itself mounted inside a bore of the motor housing 10. This characteristic is intended to be combined with the different variants exposed here for the rest of the actuator.

This external guidance is little or not used in this type of context, for example because the position of the bearing usually inside the motor makes it possible to limit the linear speed of movement of the parts of the bearing between them.

However, despite the additional radial bulk generated by the external bearing of this exemplary embodiment, this assembly provides new advantages, in particular for this type of actuator. Indeed, the space freed up in the center of the motor makes it possible to extend the travel stroke of the screw 32 when it retracts, by extending the housing 120 created in the center of the planetary pinion 12.

In addition, the choice of guiding the rotor from the outside improves the precision of its centering in relation to the centering support that the motor housing 10 forms for it, and therefore in relation to the fixed crown 21 which is integral with this motor housing. . This better centering reduces precision constraints during manufacturing and improves, for example, acoustic and wear performance, in particular for this type of differential gearbox with two different crowns mounted on common satellites.

An example of a preferred assembly method is described here for the brake caliper 51 of the has , which will only be described in its differences, but this assembly can also be carried out differently.

In this example, a motor unit 1a is assembled by coaxial mounting inside a bore of a centering support, here the motor housing 10:

on the one hand, of the outer rotor 112 of the electric motor 11, with a roller or needle bearing 15, in particular by a tight fitting, and

on the other hand, integrally in rotation, with the fixed crown 21 of the differential planetary gearbox 2, in particular by tight fitting of an attached crown 21.

Alternatively, the crown 21 is produced by direct cutting of its teeth in the material of its centering support 10.

As illustrated in , this motor group 1a therefore also includes the fixed crown 21.

According to an assembly example illustrated in , the satellites 22 and their planet carrier 220 are inserted first into the fixed ring, forming the enlarged motor group 1a'.

According to an example of assembly, the satellites and their planet carrier 220 are inserted first into the movable ring 23, as illustrated in (or in for the embodiment described below).

In both cases, the movable crown 23 is inserted into the caliper housing 41 and coupled with the screw-nut mechanism 3, here by a circlip 302 inserted for example radially through slots in the caliper housing 41, thus forming the enlarged caliper housing 4a'.

The motor group 1a ( ) or the enlarged motor group 1a' ( ) on the one hand, and the enlarged stirrup housing 4a' on the other hand, are then assembled together.

Third example embodiment

THE has illustrate a third example of an embodiment, which will only be described in its differences compared to the second example.

In this third example 52b, the motor is fixed to the motor housing 10, via a common centering support 16 forming a separate part from said housing 10. This centering support is here a cylindrical tube, for example made in a material and/or with treatments giving it better rigidity than what is useful for the rest of the motor housing 10. In this example the fixed crown 21 is attached and fixed on this centering support 16 (as indicated by the ovals on the figures), for example by tight fitting. Alternatively, the crown is directly cut into the material of this centering support.

Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

Nomenclature

1, 1a motor group

1', 1a' enlarged motor unit (pre-assembled with satellites)

10 motor housing, motor housing forming centering support

101 motor housing centering bracket, for rotor bearing

102 engine housing skirt, centering support for fixed ring gear

105 motor housing assembly clip to caliper housing

11 motor

110 stator interior housing

111 stator

112 rotor

117 engine intermediate cover

118 electronic card

119 radiator cover

12 hollow planetary gear

120 planet gear inner housing

13 planetary gear shaft

14 planetary gear shaft bearings

15 rotor outer guide bearings

16 centering support common to the rotor and fixed crown

162 part of the common centering support, forming support for the fixed crown

191,192 motor electrical connectors

2 differential epicyclic gearbox

204 cylindrical shock absorber

21 fixed crown

211 anti-rotation notches of the fixed crown

213 fixed crown skirt

22 satellites

220 planet carrier ring

23 moving crown

231 movable crown coupling splines

3 screw-nut mechanism

302 circlip for assembling the movable crown with the nut of the screw-nut

31 rotating movable nut

311 nut support flange

312 nut mating grooves

313 balls of the screw-nut mechanism

32 fixed rotating screws

323 nut rotating coupling shape

33 support plate - brake piston

333 screw for fixing the support plate on the screw

335 anti-rotation notches on the piston support plate

4 stirrup

4', 4a' widened caliper housing (pre-assembled with screw-nut)

401 caliper housing rear sleeve

41 brake housing, caliper housing

410 caliper housing housing

411 axial thrust bearing

412 rolling guide bearing

413 piston dust seal

42 caliper nose, outer caliper branch

43 caliper nose assembly screws to caliper housing

4', 4a' widened caliper housing (pre-assembled with screw-nut)

501 screed

502 inner clamping pad

503 external clamping pad

509 brake disc

51 brake (M1)

52a brake (M2)

52b brake (M3)

F1 tightening force

Claims (19)

Linear brake actuator (51, 52a, 52b) driven by an electric motor (11), in particular for road vehicles and/or automobiles, said actuator being mounted or intended to be mounted in a brake housing (41) which has a housing crossing (410) between a front side directed towards the disc and a rear side opposite the front side,
said actuator comprising a differential planetary gearbox (2) coaxial with the motor, which gearbox is driven at the input by a planetary pinion (12), which drives a group of satellites (22) which each mesh at the same time on a fixed ring gear (21) and on a movable crown (23), which crowns (21, 23) carry numbers of teeth different from each other,
which movable crown (23) rotates a reversible screw-nut mechanism (3) which produces a linear drive of a brake piston between a retracted position and an extended position,
so as to exert linear support in a so-called forward direction to produce a clamping force (F1) on a disc between clamping pads (502, 503),
in an irreversible manner at the level of the differential planetary gearbox (2), in the sense that a linear force exerted on the brake piston (33) in the direction of release will be blocked by said actuator, independently of the electric motor (11) and even if the screw-nut mechanism (3) does not itself present such irreversibility. Linear brake actuator (51) according to the preceding claim, characterized in that the nut (31) of the screw-nut mechanism is fixed in translation and is driven in rotation by the movable crown (23), and cooperates with a screw ( 32) fixed in rotation to move said screw in translation and thus produce said linear drive,
which screw (32) extends axially inside a housing (120) provided inside said input planetary pinion (12) when in the retracted position. Linear brake actuator (51) according to any one of the preceding claims, characterized in that it comprises a motor (11) of a type with an external rotor (112) and internal stator (111),
and in that the input planetary pinion (12) is driven by the rotor (112) and is carried by a shaft (13) which is guided in rotation by one or more bearings (14) mounted inside the stator (111). Linear brake actuator (52a, 52b) according to any one of claims 1 to 2, characterized in that it comprises a motor (11) of a type with an external rotor (112) and internal stator (111),
in that its rotor (112) is guided in rotation inside one or more bearings (15) mounted in a bore of at least one centering support (101, 16), which is integral with the fixed crown (21). Linear brake actuator (52b) according to the preceding claim, characterized in that the screw (32) of the screw-nut mechanism (3) extends axially inside a stator housing (110) provided at the interior of the stator (111). Linear brake actuator (52a, 52b) according to any one of Claims 4 to 5, characterized in that the same centering support (101, 16), made in a single piece and for example made of a single material, carries or has the same shape. both the fixed crown (21) and a guide bearing (15) for the rotor (112). Linear brake actuator (52b) according to the preceding claim, characterized in that the motor is fixed to a housing, which can be the brake housing (41) or a motor housing (10), via a support. common centering (16) forming a separate part of said housing (10). Linear brake actuator (51, 52a, 52b) according to any one of the preceding claims, characterized in that the screw (32) is integral with a support plate (33) acting as a brake piston which transmits linear actuation to at least one clamping shoe (502). 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 bearings (412) mounted inside a bore (410) provided in the brake housing (41); And
in axial translation, by abutment against an axial bearing face of a shoulder of the brake housing directed towards the front side, via at least one rolling bearing (411) disposed between said front face and a part of the nut (32) extending radially to form a support collar (311). 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 planetary pinion (12) is integral with the rotor and is carried by or integrated into a shaft (13) which extends inside the stator (111) where it is guided in rotation by a rolling bearing ( 14); And
the movable crown (23) is movable in rotation from inside the fixed crown (21) or its centering support (10); And
the movable crown (23) is secured to the nut (31) in rotation by cooperation of splines or teeth or longitudinal grooves (231, 312); And
the fixed crown (21) is fitted in or around a bore formed in a housing (410) provided in the brake housing (41),
the nut (31) is mounted freely in rotation in a bore of the housing (410) of the brake housing (41), which ends in a shoulder having a bearing face directed towards the front and on which the nut comes into axial abutment (411); And
the screw (32) is integral with a support plate (33) forming a brake piston and which keeps said screw (32) fixed in rotation, in particular by rotating coupling (33, 323) of said piston (33) with a braking pad (502) which receives its linear force (F1) and is itself kept in rotation by a fixed yoke (501). 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
said rotor (111) is guided in rotation by an external bearing (15) mounted inside a centering element (10, 16), and is integral in rotation with the input planetary pinion (12); And
said stator (11) is hollow in the sense that it has, over at least half the length of the motor (11), an axial housing (110) arranged to allow the passage of the screw (32) inside the pinion input sun gear (12) and said stator (111);
the fixed crown (21) is mounted on or integrated into a centering support (10, 16) which receives at least one of the motor bearings (15) or forms a part of said motor bearing, that is to say that this centering support (10, 16) is made of a single material or with continuity of material between a part (101) forming or receiving said motor bearing (15) and a part (102, 162) forming or receiving the fixed crown (21); And
the movable crown (23) is movable in rotation inside the fixed crown (21) or its centering support (10, 16); And
the movable crown (23) is secured to the nut (31) in rotation by cooperation of longitudinal splines or teeth or grooves (231, 312); And
the fixed crown (21) or its centering support (10, 16) is fitted in or around a housing (410) provided in the brake housing (41),
the nut (31) is mounted freely in rotation in a bore of the housing (410) of the brake housing (41), which ends in a shoulder having a bearing face directed towards the front and on which the nut comes into axial abutment (411); And
the screw (32) is integral (33, 323) with a support plate (33) forming a brake piston and which keeps said screw (32) fixed in rotation, in particular by rotating coupling (335) of said piston (33). ) with a braking pad (502) which receives its linear force (F1) and is itself kept in rotation by a fixed yoke (501). Linear brake actuator according to any one of the preceding claims, characterized in that the movable crown (23) is movable in rotation inside the fixed crown (21) or its centering support (10, 16). Linear brake actuator according to any one of the preceding claims, characterized in that the fixed ring gear (21) is arranged in a bore of the brake housing housing (410), where it is held radially by means of at at least one cylindrical shock absorber (204) with at least radial damping, in particular formed entirely or partly of an elastomeric material,
said cylindrical shock absorber (204) being for example compressed between the brake housing (41) and a skirt secured to the fixed crown (21), which skirt extends for example towards and around the movable crown (23). Linear brake actuator according to any one of the preceding claims, characterized in that the screw comes into linear support inside a hydraulic piston which is coaxial with it, which produces a brake piston with selectively electrical and/or actuation. hydraulic. Disc brake with floating or sliding caliper (51, 52a, 52b), in particular for road vehicles and/or automobiles, this brake comprising a caliper (4) forming two branches intended to span at least one brake disc to apply a torque to it braking by tightening at least two braking pads (502, 503) on both faces of this disc, at least one of these branches comprising a body forming a caliper housing (41) forming the brake housing , receiving a linear actuation mechanism arranged to produce this tightening by linearly moving at least one brake piston (33) which presses on at least one clamping pad (502),
characterized in that this linear actuation mechanism comprises at least one linear brake actuator according to any one of claims 1 to 13, arranged to produce a clamping and loosening force, linear support or traction at the rear of a support plate forming a brake piston (33) devoid of hydraulic actuation. Disc brake with floating or sliding caliper, in particular for road vehicles and/or automobiles, this brake comprising a caliper forming two branches intended to span at least one brake disc to apply a braking torque to it by tightening at least two pads braking on both faces of this disc, at least one of these branches comprising a body forming a brake housing receiving a linear actuation mechanism arranged to produce this tightening by linearly moving at least one brake piston which presses on at least one clamping pad,
characterized in that this linear actuation mechanism comprises at least one linear brake actuator according to any one of claims 1 to 14, arranged to produce a clamping force by linear support inside a hydraulic piston housed in a hydraulic chamber controlled by a hydraulic circuit. Vehicle or vehicle subassembly, in particular road and/or automobile, comprising a brake according to any one of claims 15 to 16 or a brake comprising an actuator according to any one of claims 1 to 14. Method of 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 subassembly according to claim 17, in combination with claim 2, characterized in that it comprises:
on the one hand a coaxial mounting of a shaft (13) of hollow planetary pinion (12) inside the stator (111) of an electric motor (11) with external rotor (112), with a bearing at one or several bearings (14), in particular by a tight fit, thus forming a motor group (1), or provision of such a motor group;
on the other hand the following steps:
insertion inside the brake housing (41): on the rear side of the movable crown (23); and on the front side of an assembly comprising the screw-nut mechanism (3), by mounting its movable nut (31) in the housing (410) of the brake housing by means of at least one bearing providing guidance for said nut movable in rotation by rolling (412) and in axial abutment towards the rear by rolling (411);
coupling in rotation (231-312), and preferably also in translation, between the movable crown (23) and the movable nut (31), during insertion or subsequently. Method of 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 it includes:
on the one hand an assembly of a motor group (1a), or a supply of a motor group thus assembled, by coaxial mounting inside the centering support (10, 16):
on the one hand, of the outer rotor (112) of the electric motor (11), with a bearing with one or more bearings (15), in particular by a tight fitting, and
on the other hand, integrally in rotation, with the fixed crown (21) of the differential planetary gearbox (2), in particular by tight fitting of an attached crown (21) or by direct cutting of the teeth of said crown in the material of the support element (10, 16);
on the other hand the following steps:
insertion, inside the brake housing (41): on the rear side, of the movable crown (23); and on the front side, of an assembly comprising the screw-nut mechanism (3), by mounting its movable nut (31) in the housing (410) of the brake housing by means of at least one bearing providing guidance for said movable nut relative to the brake housing, in rotation by bearing (412) and in axial abutment towards the rear by bearing (411),
coupling in rotation (231-312), and preferably also in translation, between the movable crown (23) and the movable nut (31), during insertion or subsequently.