Mechatronic braking system

Abstract

The present invention comprises an electromechanical braking module incorporating an electric drive system of a brake calliper, comprising a housing (700) containing a main motor (100), the rotary shaft (115) of which has a means for coupling with a transmission member of the brake calliper, and an electric actuator (200) controlling a locking system (400) immobilising an element secured to the shaft of the main motor (100), characterised in that: - the braking system comprises a single electronic board (500) arranged in a plane perpendicular to the shaft of the main motor (100), the coils (150) of the main motor (100) being electrically connected to the electronic board (500); - the median plane (930) of the locking system is arranged between the plane (920) of the electronic board (500) and the plane of the front surface (910) of the yoke of the stator (120) of the main motor (100), closest to the electronic board (500); - and the element secured to the shaft of the main motor (100) and the means for driving the transmission member of the calliper are located on either side of the stator yoke of the main motor (100).

Description

Mechatronic braking system Scope of the invention

[0001] The present invention relates to a complete electromechanical braking module integrating an electromechanical system for driving a brake caliper and an electronic parking brake (EPB) means, and more particularly, an EPB which acts on the caliper drive system to lock it in the closed position during parking phases.

[0002] When an ECU (electronic control unit) receives electronic information and drives a motor to generate torque and rotation during braking, a screw-nut system coupled to the motor moves towards a brake pad. The brake pad, receiving the axial force from the screw-nut system, moves towards a wheel disc and generates a braking force by pressurizing the wheel disc.

[0003] When parking brake functions are integrated, such a complex mechanism can become larger, heavier, and bulkier than a hydraulic caliper. State of the art

[0004] Prior art is known US patent 7950503 concerning a motor-driven disc brake system capable of preventing a pressure element from moving beyond a predetermined position when a motor is stopped. When a system stop command is issued, an alternating interval A and B process is carried out to intermittently reduce the motor current and consequently progressively reduce the motor displacement, so that a return force, such as torque stored in a helical spring (return spring), is gradually expended on a return displacement of a motor and piston, thus preventing the rotational speed of a rotor from increasing.

[0005] Patent application JP2023148408 relates to a compact and simple vehicle braking system using an electric motor (20) to actuate a braking mechanism. A gearbox (30) converts the rotary motion of the motor into linear motion applied to the brake pads (4) against the disc (3). A locking system (50), using a solenoid (51) and a rotary restrictor device (52), immobilizes the gearbox to maintain pressure on the pads. This architecture enables effective braking and secure holding of the vehicle in a stationary position, reducing the complexity and cost of the device.

[0006] US patent 11932214 relates to an electromechanical braking system that uses an electric motor to actuate a disc brake. The device includes a gearbox, a rotary-to-linear conversion mechanism, and a locking system that maintains pressure on the brake pads after activation. An integrated electronic control unit dynamically adjusts the braking force according to vehicle conditions. A sensor monitors pad wear, and a compensation mechanism automatically adjusts the piston position. The compact architecture reduces energy losses and improves system durability through optimized force distribution.

[0007] Patent application WO2023166434 relates to a brake caliper for a disc brake comprising a caliper body with two lateral walls defining a space for the brake disc, and a connecting structure linking these walls by overlapping the disc space.

[0008] US patent 6626270 describes a brake caliper with an internal electric motor. This motor drives a two-stage planetary gear system: the first stage meshes with the motor shaft and the inside of the piston, while the second interacts with the first and a ball screw. The rotation of the ball screw converts rotary motion into linear motion, thus actuating the piston to apply the brake. A parking brake mechanism is also integrated, using a parking brake lever that engages the teeth of a pulley mounted on the motor shaft. Disadvantages of prior art

[0009] Prior art solutions present a space-related problem and do not allow for optimal integration of the main brake and parking brake. The brake caliper is positioned on the vehicle to exert pressure via the brake pads on the brake disc, clamping the disc. It must be highly robust while occupying a limited volume to allow for seamless integration. Solution provided by the invention

[0010] To address this space constraint, the present invention relates to an electromechanical braking module incorporating an electric drive system for a brake caliper. This module comprises a housing containing a main motor, the rotating shaft of which has a coupling means for a transmission element of the brake caliper, and an electric actuator controlling a locking system that immobilizes a component attached to the shaft of said main motor. The braking system according to the invention includes a single electronic circuit board arranged in a plane perpendicular to the axis of the main motor, the coils of said main motor being electrically connected to said electronic circuit board. The median plane of the locking system is located between the plane of said electronic circuit board and the plane of the front surface of the stator head of the main motor, closest to said electronic circuit board.The element attached to the axis of the main motor and the means of driving said transmission member of the caliper are located on either side of the stator cylinder head of said main motor.

[0011] The element attached to the shaft of said main motor, which is immobilized by the locking system, is a ratchet wheel, said locking system comprising a locking bar engaging in said ratchet wheel to ensure its immobilization.

[0012] The locking bar is engaged in a moving part in translation by a screw-nut transformation in cooperation with an axis driven by a secondary electric motor.

[0013] Advantageously, the electric actuator is equipped with a rotor, the axes of rotation of the rotor of the main motor and of the rotor of the electric actuator are parallel to each other and both orthogonal to the plane of the electronic board.

[0014] According to one variant, the entire locking system actuator is arranged between the transverse plane of said electronic board and the plane of the front surface of the stator cylinder head.

[0015] Advantageously, the coils of said locking actuator are also electrically connected to said electronic board.

[0016] Preferably, the shaft of said main motor rotor is provided with a target mounted between the median plane of said locking system and said electronic board.

[0017] According to a particular embodiment, said target has magnetic indexing and said electronic card is equipped with a magnetosensitive probe disposed opposite said target,

[0018] Alternatively, the target is secured to said element which is fixed to the axis of said main motor.

[0019] According to a particular embodiment, the electric actuator of the locking system is a geared motor comprising a mechanism for transforming the rotary motion of an electric motor into a linear displacement motion of said locking bar.

[0020] Preferably, the electric actuator controlling said locking system is disposed between the transverse plane of the electronic board and the median longitudinal plane of said stator cylinder head of said main engine.

[0021] Depending on specific variations:

[0022] - the electronic card includes a probe positioned opposite a target fixed on said moving part of said locking system to obtain position information of said locking system.

[0023] - the electronic board includes the means for controlling the main motor and the electric actuator.

[0024] - the electronic board is also integrated into the housing containing the main motor and the electric actuator.

[0025] - the locking system includes a spring disposed between said moving part and said locking bar, to push said locking bar in the direction of said ratchet wheel

[0026] - the module also includes a force sensor providing the electronic circuit with information based on the force exerted on the brake pads.

[0027] Detailed description of a non-limiting example of implementation

[0028] The present invention will be better understood upon reading the following description, concerning a non-limiting example of an embodiment illustrated by the accompanying drawings where:

[0029] Figure 1 represents an exploded view of an electromechanical braking module according to the invention.

[0030] This represents a schematic view of a braking module according to the invention.

[0031] This represents a side view of the braking module according to the embodiment shown in,

[0032] larepresents an exploded perspective view of the brake locking system according to the embodiment shown in. General principle of the invention

[0033] The invention relates to a braking module integrating the functions of service brake, progressive braking by a caliper activated by a main electric motor (100), and a locking system (400), motorized by an electric actuator (200), ensuring the parking brake function, by means of a ratchet wheel (450).

[0034] To reduce the transverse bulk and allow optimal integration on the car chassis, this module according to the invention provides for the arrangement of all the electromechanical components (100, 200, 400) within the volume of the housing (700) located between the transverse base (910

[0035] ) of the housing (700), bracket side, and a single electronic board (500), the housing (700) being closed on the opposite side to the bottom by a cover (800).

[0036] The main motor (100) is electrically and mechanically connected to this electronic board (500) by terminals (190). The locking system (400) has a median transverse plane (930), parallel to the plane (920) of the electronic board (500), and located between said plane (920) of the electronic board (500) and the plane (910) of the front surface of the stator head (120) of the main motor (100) facing the electronic board (500). Preferably, the locking system (400) interacts with the ratchet wheel (450) by means of a locking bar (230) driven in translation by the electric actuator (200). This locking bar (230) has a target (350) moving in relation to a probe (530) attached to the electronic board (500), and preferably directly soldered to the latter, to provide information on the actual position of the locking bar (230).

[0037] The axis of rotation of the main motor rotor (100) is orthogonal to the plane (920) of the electronic board (500).

[0038] The electric actuator (200) is also electrically and mechanically connected to said electronic board (500) by terminals (290).

[0039] The distal end of the main motor rotor (100) is provided with another target (300) placed opposite another probe (520) attached to the same electronic board (500), and also preferably directly soldered onto the latter, to provide information on the angular position of the rotor (110) causing the movement of the caliper.

[0040] Geometric positioning of the module components

[0041] The relative positioning of the components is illustrated by figures 2 and 3, the latter representing a schematic cross-sectional view of a module according to the invention and the former representing more particularly a side view of the embodiment presented in.

[0042] The housing (700) is made of a molded part, for example of plastic, and has a substantially cylindrical protrusion (710) in which the main motor (100) is housed. The bottom (711) of this cylindrical protrusion (710) is traversed by the shaft (115) of the rotor (110) of the main motor (100), to allow its coupling with the mechanical elements of the caliper ensuring the transfer of power to the jaws by means of a motion transformation mechanism.

[0043] Optionally, the housing (700) is made by overmolding the stator (120) of the main motor (100).

[0044] The shaft (115) of the motor rotor (100) has two bearings (116, 117). The rear bearing (116), located on the side of the shaft interfacing with the yoke, is inserted into a housing provided on the bottom (711) of the protrusion (710) of the housing (700). The front bearing (117) is housed in a support (118), preferably an overmolded plastic support, which is inserted into another housing (712) on the front face of the protrusion (710) of the housing (700), in which the stator (120) is housed, and which is then secured by welding, gluing, screwing, or any other method known to those skilled in the art.

[0045] Optionally, the rear bearing (116) is replaced by a plain bearing, the axle then being directly guided by the bearing (117), and said plain bearing.

[0046] The housing (700) further includes a secondary housing (720) to accommodate the components providing the EPB parking brake function, and in particular the electric actuator (200). It also includes an additional housing (740), on the side opposite the protrusion (710), to receive the large electronic components soldered onto the underside of the electronic board (500), for example, the capacitors.

[0047] The peripheral wall (760) of the housing (700) has shoulders (765) with screw holes for positioning and fixing the electronic board (500).

[0048] The housing (700) is closed on the opposite side of the bottom (750) and the shaft exit by a cover (800). This cover (800) may, but is not limited to, be metallic to also provide a cooling function for the electronic components soldered onto the upper surface of the electronic board (500).

[0049] The housing (700) also includes a connector (730), placed in the example described on the peripheral wall (760), but which could also extend from the bottom (750) of the housing or be associated with the cover (800).

[0050] In sagittal (transverse-longitudinal) section illustrated by the, the electronic board (500) is positioned in the upper part of the housing (700), just below the cover (800), with all the mechanical components located in the lower part of the housing (700), below the electronic board (500).

[0051] All interaction functions between the electronics and the electromechanical components are ensured from the lower surface of the electronic board (500).

[0052] In particular: The angular position of the rotor (110) is read by a position sensor whose probe (520) is soldered to the underside of the electronic board (500), opposite the target (300). In the example described, the target (300) is a diametrically magnetized disc magnet mounted on the front end of the rotor shaft (115). The probe (520) is, in this case, magnetosensitive, typically a Hall effect probe. The linear position of the locking bar (230) is read by a position sensor whose probe (530) is soldered to the underside of the electronic board (500), opposite the target (350). In the example described, the target (350) is a rotating magnet, as described in patent WO2007099238, attached to the locking bar (230). The probe (530) is in this case magneto-sensitive, typically a Hall effect probe.The power supply to the coils (150) of the main motor (100) is provided by press-fit type terminals (190) inserted into conductive holes in the electronic board (500). The power supply to the electric actuator (200) is provided by press-fit type terminals (290) inserted into conductive holes in the electronic board (500). The power supply and signal reading of a force sensor connected to a connector (735) housed in the bottom (711) of the housing (700) is provided by press-fit type terminals (290) inserted into conductive holes in the electronic board (500).

[0053] Furthermore, the grounding of the stator (120) of the main motor (100) is ensured by a bore provided in the stator lamination block, in which a pin (196) is housed. The pin's front head bears against a metallic spring element (195) welded to a conductive track on the electronic board (500). Positioning the electronic board (500) compresses the spring element (195) against the end of the pin (196), ensuring proper electrical conductivity between the conductive track and the stator lamination block (120).

[0054] To make the system very compact, the locking system (400) is positioned between the electronic board (500) and the main motor (100) and is designed to engage with the ratchet wheel (450) carried by the shaft (115) of the main motor (100). More specifically, the shaft (115) carrying the rotor (110) extends beyond the plane of the front surface (910) of the stator laminations (120) in the direction of the electronic board (500), and its end carries a target (300) that cooperates with a probe (520) welded to the surface of the electronic board (500) to measure the angular position of the rotor (110). The ratchet wheel (450) is supported by the protruding portion of the shaft (115) located between the front surface (910) and the target (300). The locking system (400) has a median plane (930), this median plane (930) being located between the front surface (910) of the stator head (120) and the transverse plane (920) of the electronic board (500).More specifically, the electric actuator (200) driving the locking system (400) is entirely located between the front surface (910) of the stator head (120) and the transverse plane (920) of the electronic board (500). In an even more advantageous configuration, the entire locking system (400) is located between the front surface (910) of the stator head (120) and the transverse plane (920) of the electronic board (500).

[0055] The very compact arrangement proposed with the direct proximity of the electronic board (500) with the main motor (100) and the locking system (400) allows with a single control electronic to: Measure the state of the locking system (400) in the position of engagement or not of the locking bar, Measure the angular position of the rotor of the main motor (100) and in addition that of the ratchet wheel (450), Support the control means of the main motor (100), Support the control means of the electric actuator (200) of the locking system (400).

[0056] In the embodiment presented, the position sensor is equipped with a probe (520), of the magneto-sensitive type, soldered onto the electronic board (500) and the target is a permanent magnet, but this is in no way limiting of the invention and a person skilled in the art could well imagine that the position sensor is an inductive type sensor, the probe (520) then being made up of a set of conductive tracks integrated into the electronic board (500), allowing to excite and analyze the response of the conductive target (300) to this excitation, or any other known alternative of non-contact position measurement.

[0057] Detailed operation of the locking system (400)

[0058] Figure 1 represents an exploded view of a locking system (400) for the main motor (100), which, in conjunction with the ratchet wheel (450), provides the parking brake function. The electric actuator (200) of the locking system (400), in the form of a secondary electric motor with a motion converter, is integrated into a secondary housing (790) which is attached to the main housing (700). This secondary housing (790) has two parts: the upper part (791), located on the electronic board side, is preferably made of plastic by overmolding the stator (220) of the secondary motor; the lower part (792) is preferably made of molded plastic and accommodates the moving parts before assembly with the upper part (791) of the secondary housing (790).The housing includes a wound stator (220) positioned beneath the electronic board (500), with the coils (250) electrically connected to the electronic board (500) by terminals (290). This stator (220) has a transverse plane parallel to the plane (920) of the electronic board (500) and drives the rotation of a rotor (210) around an axis oriented perpendicular to the plane (920) of the electronic board (500). Thus, the axes of rotation of the main motor (100) and the electric actuator (200) are parallel to each other and both orthogonal to the plane (920) of the electronic board (500), resulting in a particularly compact axial configuration at the secondary housing (720). The rotor (210) includes a worm gear (211) driving a pinion (212) mounted on a longitudinal shaft (215), so as to provide an irreversible motion transformation, only the rotational driving of the longitudinal shaft by the rotor (210) being possible.This shaft (215) has reverse threads (213, 214) on either side of the pinion (212) that interact with nuts (240, 245). The rear nut (245) is fixed to the lower part (792) of the secondary housing (790). The front nut (240) is fixed to a part (260) guided in longitudinal translation by the secondary housing (790).

[0059] In the example described, this part (260) is in the form of a rectangular protrusion of the nut (240) extending in the direction of the electronic board (500) on one side and the main motor (100) on the other, so as to provide a support for the locking bar (230). Said locking bar (230) has a nose (231), adapted to engage in the ratchet wheel (450), and extends in the opposite direction by two legs (232, 233), each ending in a hook (234) so ​​as to form a slot (235) into which the part (260) is inserted. The locking bar (230) is guided in longitudinal translation in the upper part (791) and is stopped in longitudinal translation by the hooks (234) bearing against the part (260), itself being guided in translation and stopped longitudinally by the upper part (791).Since the opening (235) has a greater longitudinal extension than the part (260), movement in the direction of the ratchet wheel of the locking bar (230) relative to the part (260) is possible. The part (260) is also provided with a longitudinal cylindrical cavity, opening towards the front and closed at the bottom, on the side of the nut (240), this cylindrical cavity being suitable for receiving a compression spring (265), mounted in compression between the bottom of the cavity and the rear end (236) of the nose (231) of the locking bar (230). This spring (265) allows movement of the locking bar (230), when the secondary motor is not powered, so that when the locking bar (230) is engaged in the ratchet wheel (450), rotation of the ratchet wheel (450) in a direction ensuring clamping of the caliper is possible, but rotation in the direction of loosening is prohibited.Indeed, the tooth profile of the ratchet wheel (450) generates a longitudinal force capable of moving the locking bar (230) when the ratchet wheel (450) rotates in the direction of caliper clamping. Conversely, the force exerted by the teeth in the opposite direction causes the nose (231) of the locking bar to abut tangentially against a tooth, thus blocking rotation. During rotation in the caliper clamping direction, the spring (265) allows the nose (231) of the locking bar (230) to re-engage with the ratchet wheel (450) as each tooth passes. This spring therefore also ensures that the bar abuts against a tooth regardless of the position of the ratchet wheel (450) when the locking bar (230) reaches the engaged position, this position being determined by the position sensor consisting of a target (350) and a probe (530).Indeed, in the engagement position, the compression force of the spring keeps the nose (231) always in frontal contact with the ratchet wheel (450) and thus prevents rotation in the loosening direction of more than one tooth.

[0060] The secondary motor is arranged in its housing so that its stator (220) is located on the side of the electronic board (500) and the worm gear driven by the rotor (210) is located on the opposite side.

[0061] The upper part (791) of the secondary housing (790), located opposite the electronic board (500), has a light (793) through which a magnet serving as a target (350) passes, mounted rigidly on the locking bar (230) and extending over the entire travel of said locking bar (230), allowing, by cooperation with a probe (530) soldered onto the electronic board, to provide information on the absolute position of the locking bar (230) to verify its state of engagement in the ratchet wheel (450).

[0062] The upper part (791) of the secondary housing (790) preferably has three openings (795) opposite the rotor (210) for positioning three magnetosensitive probes, soldered to the lower part of the electronic board (500), necessary for controlling the secondary motor. Control by three probes is a computationally inexpensive solution, but any type of control remains compatible with the invention, as long as the locking system ensures reliable and controlled engagement of the locking bar (230) in the ratchet wheel (450).

[0063] The secondary motor stator is grounded by a bore in the stator laminations (220), which houses a compression spring (295). The front end of this spring bears against a conductive track on the electronic board (500) at one longitudinal end, and against an inclined plane (799) on the lower part (792) of the secondary housing (790) at the other. Installing the electronic board (500) compresses the spring (295), and its contact with the inclined plane (799) of the housing induces a transverse displacement of the spring, thus forcing it into contact with the stator bore (220). Alternatively, the transverse expansion of the spring (295) during compression could also be used to ensure good electrical contact with the stator bore (220).

[0064] In the embodiment presented, the position sensor is equipped with a probe (530), of the magneto-sensitive type, soldered onto the electronic board (500) and the target (350) is a permanent magnet, but this is in no way limiting of the invention and a person skilled in the art could well imagine that the position sensor is an inductive type sensor, the probe (530) then being made up of a set of conductive tracks integrated into the electronic board (500), allowing to excite and analyze the response of the conductive target (350) to this excitation, or any other known alternative of non-contact position measurement. Implementation variations

[0065] The illustrated examples are in no way limiting to the invention, and it is specifically envisaged that, in variations not shown, the position sensors may be inductive, capacitive, magnetoresistive, optical, or any other type of position sensor known to those skilled in the art. It is also envisaged that the locking system may be a solenoid-type linear actuator or a rotary system, the essential characteristic being that this locking system be located between the electronic board and the midplane of the main motor's stator.

Claims

Electromechanical braking module integrating an electric drive system for a brake caliper, comprising a housing (700) containing a main motor (100), the rotating shaft of which (115) has a coupling means with a transmission element of the brake caliper, and an electric actuator (200) controlling a locking system (400) immobilizing an element fixed to the shaft of said main motor (100), characterized in that said braking system comprises an electronic board (500) disposed in a plane perpendicular to the axis of the main motor (100), the coils (150) of said main motor (100) being electrically connected to said electronic board (500), and in that the median plane (930) of said locking system is disposed between the plane (920) of said electronic board (500) and the plane of the front surface (910) of the stator head (120) of said main motor (100),the closest to said electronic board (500) and in that said element integral with the shaft of said main motor (100) and said drive means of said caliper transmission member are located on either side of the stator cylinder head of said main motor (100). Electromechanical braking module according to claim 1 characterized in that the element integral with the shaft of said main motor (100) immobilized by the locking system (400), is a ratchet wheel (450), said locking system (400) comprising a locking bar (230) engaging in said ratchet wheel (450) to ensure its immobilization. Electromechanical braking module according to claim 2 characterized in that said locking bar (230) is engaged in a moving part (260) in translation by a screw-nut transformation in cooperation with an axis (215) driven by a secondary electric motor. Electromechanical braking module according to claim 1 characterized in that the electric actuator (200) is provided with a rotor (210), the axes of rotation of the rotor (110) of the main motor (100) and of the rotor (210) of the electric actuator (200) are parallel to each other and both orthogonal to the plane (920) of the electronic board (500). Electromechanical braking module according to claim 1 characterized in that the entire locking system actuator (400) is disposed between the transverse plane (920) of said electronic card (500) and the plane of the front surface (910) of the stator cylinder head. Electromechanical braking module according to claim 1 characterized in that the coils (250) of said locking actuator (200) are also electrically connected to said electronic board (500). Electromechanical braking module according to claim 1 characterized in that the shaft of said rotor (110) of the main motor (100) is provided with a target (300) mounted between the median plane (930) of said locking system (400) and said electronic board (500). Electromechanical braking module according to the preceding claim characterized in that said target (300) has magnetic indexing and in that said electronic card (500) is provided with a magneto-sensitive probe (520) disposed opposite said target (300), Electromechanical braking module according to claim 1 characterized in that said target (300) is fixed to said element fixed to the shaft of said main motor (100). Electromechanical braking module according to claim 3 characterized in that said electric actuator (200) of said locking system (400) is a geared motor comprising a mechanism for transforming the rotary motion of an electric motor into a linear displacement motion of said locking bar (230). Electromechanical braking module according to claim 1 characterized in that said electric actuator (200) controlling said locking system (400) is disposed between the transverse plane (920) of the electronic board (500) and the median longitudinal plane of said stator cylinder head of said main motor (100). Electromechanical braking module according to claim 3 characterized in that said electronic card (500) includes a probe (530) disposed opposite a target (350) fixed on said moving part (260) of said locking system (400). Electromechanical braking module according to claim 1 characterized in that said electronic card (500) includes the means for controlling the main motor (100) and the electric actuator (200). Electromechanical braking module according to claim 1 characterized in that said electronic card (500) is also integrated into the housing (700) comprising the main motor (100) and the electric actuator (200). Electromechanical braking module according to claim 3 characterized in that said locking system (400) comprises a spring (265) disposed between said moving part (260) and said locking bar (230), to push said locking bar (230) in the direction of said ratchet wheel (450). Electromechanical braking module according to claim 1 characterized in that it further comprises a force sensor providing said electronic circuit with information as a function of the force exerted on the brake pads.

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