Hydraulic and electromechanical service and parking disc brakes

Abstract

The hydraulic and electromechanical service and parking disc brake (1) comprises a service brake system (20) having at least one hydraulic actuator (65), a parking brake system (21) having a transmission irreversibility of at least one electromechanical actuator (64), a control system (22) connected to the service brake system (20) and the parking system (21), and a user interface (23), wherein a translation member (17) of the electromechanical actuator (64) is non-rotatably constrained relative to the caliper (2) by an anti-rotation shape connection with a guide portion (35) that is integral with the caliper (2) and arranged on the rear side opposite to the free end of the translation member (17).

Description

[Technical Field]

[0001] The present invention relates to hydraulic and electromechanical service and parking disc brakes, especially for motor vehicles. [Background technology]

[0002] Electromechanical parking and emergency brakes are known that are equipped with an electrically operated rotary actuator and a screw-and-nut thrust assembly acting on the hydraulic piston of a service disc brake or on a special parking piston if the parking brake is an autonomous structure.

[0003] Electromechanical disc brakes are also known that include a caliper body having two walls arranged on either side of a brake disc and connected to each other by two or more connecting bridges extending across the disc. The inboard wall of the caliper body has holes for accommodating fastening screws for rotationally and translationally fixing the caliper body to the vehicle suspension. The caliper body's two walls have seats for accommodating pads facing the brake disc and bearing a friction material coating, and at least one of the walls defines one or more seats for pistons adapted to clamp the pads against the brake disc to generate braking force. The pistons are connected to an electromechanical actuator, which may comprise, for example, an electric motor, a transmission, and a reducer, and rotates a screw that engages with a corresponding nut. The nut, which is locked against rotation but free to translate, engages with or forms an integral part of the piston. Rotation of the screw thus causes translation of the piston and the corresponding pad relative to the brake disc.

[0004] The engagement between the screw and nut of an electromechanical actuator (for parking brakes) can be configured to be mechanically irreversible, i.e., an input rotational moment causes an output translational motion, but an input translational force (in the opposite direction) does not cause an output rotation. As a result, after applying the torque required to clamp the piston and pads against the brake band of the brake disc, the clamping remains self-locked unless power is applied to the motor.

[0005] The mechanical irreversibility is achieved by selecting the friction angle and inclination of the contact points of the threads or teeth of the two gear components so as to prevent the transfer of motion from the translational element to the rotational element. This concept also applies to the brake according to the present invention.

[0006] The electric motor and transmission must be electrically and mechanically sized to provide a torque that will apply the required parking force, minus friction, to the piston.

[0007] Due to the considerable dimensions of the electromechanical (parking) actuator, in the prior art, electromechanical parking brakes are usually integrated into so-called floating calipers, which are characterized by a unilateral hydraulic and electromechanical actuator, pointing towards the inside of the vehicle, making it possible to install the electromechanical actuator only inside the caliper, which reduces space issues.

[0008] Integrating electromechanical parking actuators into so-called fixed calipers with bilateral hydraulic actuators is currently problematic, since in addition to the hydraulic actuators, additional electromechanical actuators must be provided on both sides of the caliper, on the side facing the outside of the vehicle directly towards the wheel rim. The concept of a fixed caliper with bilateral hydraulic and bilateral electromechanical actuators still suffers from strong technical prejudices, mainly due to its high weight and large overall dimensions.

[0009] A further problem with the prior art relates to the mechanism that converts the rotational motion of the electric motor into translational motion applied to the piston. The sliding element (screw or nut) is locked against rotation by a positive fit with the piston, and its rotation is prevented only by friction with the lining and the backplate of the pad against which it abuts. The strength of the piston's "anti-rotation" friction may be insufficient to prevent rotation of the piston and, therefore, of the parking mechanism's translational element. This can result in reduced piston advancement and a concomitant reduction in parking force.

[0010] Furthermore, the positive connection between the slide and the piston must achieve a translation stroke at least as long as the thickness of the friction material on the pad, which in turn must achieve at least as long as the piston stroke. Providing a translational slide zone in series with the nut-screw mechanism would add an undesirably large axial dimension.

[0011] SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic and electromechanical service and parking disc brake having features which avoid at least some of the drawbacks mentioned with reference to the prior art. Summary of the Invention

[0012] Among its general objects, a specific object of the present invention is to provide a hydraulic and electromechanical service and parking disc brake suitable for implementation with fixed calipers.

[0013] A more specific object of the present invention is to provide a hydraulic and electromechanical service and parking disc brake having smaller overall dimensions than prior art solutions.

[0014] A more specific object of the present invention is to provide a hydraulic and electromechanical service and parking disc brake having an overall light weight relative to the weight of prior art solutions.

[0015] A more specific object of the present invention is to provide hydraulic and electromechanical service and parking disc brakes in which the translational stroke of the parking mechanism is not altered by undesirable, unplanned rotational slippage of the pistons.

[0016] A more specific object of the present invention is to provide a hydraulic and electromechanical service and parking disc brake in which the rotary to transmission mechanism in the hydraulic piston-cylinder assembly is improved over the prior art.

[0017] A more specific object of the present invention is to provide a hydraulic and electromechanical service and parking disc brake having characteristics that result in greater piston displacement stroke certainty in dependence on the rotational stroke performed by the electric motor.

[0018] At least some of the aforementioned objects are achieved by a hydraulic and electromechanical service and parking disc brake according to claim 1. Some advantageous embodiments are the subject of the dependent claims.

[0019] In order to better understand the invention and to realise its advantages, some non-limiting embodiments will now be described with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a disc brake according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the disc brake in FIG. [Figure 3] FIG. 3 is a further cross-sectional view of the disc brake of FIG. [Figure 4] FIG. 4 is an enlarged view of a detail in FIG. [Figure 5] FIG. 5 is an enlarged view of a detail in FIG. [Figure 6]FIG. 6 is a cross-sectional view of a pre-assembled assembly of a disc brake according to an embodiment. [Figure 7] FIG. 7 is an exploded perspective view of components of the disc brake according to the embodiment. [Figure 8] FIG. 8 is an exploded perspective view of components of the disc brake according to the embodiment. [Figure 9] FIG. 9 is an exploded perspective view showing details of the electromechanical parking mechanism of the disc brake according to the embodiment. [Figure 10] FIG. 10 is an exploded perspective view showing details of the electromechanical parking mechanism of the disc brake according to the embodiment. [Figure 11] FIG. 11 is an exploded perspective view showing the electromechanical parking mechanism of the disc brake according to the embodiment. [Figure 12] FIG. 12 shows the electromechanical parking mechanism of FIG. 11 in an assembled state. [Figure 13] FIG. 13 shows the electromechanical parking mechanism of FIG. 11 in an assembled state. [Figure 14] FIG. 14 is a top view of the disc brake according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Caliper 2 Overview

[0022] With reference to the figures, a hydraulic and electromechanical service and parking disc brake is generally designated by the reference numeral 1. The brake 1 comprises a caliper 2 having two spaced apart side walls 3 defining a disc space 4 for accommodating a portion of a brake disc 5 (shown in dashed lines in Figure 2). The brake 1 further comprises means for fixing the caliper 2 to the vehicle suspension. For example, said fastening means comprises at least two holes defined by one of the side walls 3 and adapted to receive respective fastening screws.

[0023] The two walls 3 of the caliper 2 are connected to each other by at least one connecting structure 6 that extends across the disc space 4, and each of the walls 3 or the supporting portions connected thereto defines at least one seat for receiving or supporting a pad 7.

[0024] According to an embodiment, the support has support pins 8 connected to both side walls 3 and spanning the disc space 4. The pad support plate defines holes or seats 9 at its upper part (radially outward with respect to the axis of the brake disc) for receiving the support pins 8 to restrain the pads 7 from the caliper 2 in a depending manner.

[0025] Overview of the service brake system 20

[0026] The brake 1 further comprises a service brake system 20. The service brake system 20 comprises (particularly if the caliper 2 is a fixed caliper) two hydraulic actuators 65, each arranged on one of the side walls 3, which can be actuated to clamp the pads 7 against the brake disc 5.

[0027] Each hydraulic actuator 65 has a hydraulic cylinder 10 formed in the side wall 3 and a piston 11 housed in the hydraulic cylinder 10 and having a free end 14 facing the pad 7. The interior space 12 of the hydraulic cylinder 10 is in communication with a system 13 that supplies and pressurizes hydraulic fluid to apply hydraulic pressure to the piston 11 to translate the piston 11 in an actuation direction 19 toward the brake disc 5 and pressurize the pad 7 against the brake disc 5.

[0028] According to an alternative embodiment, for example when the caliper 2 is a so-called floating caliper, the service brake system 20 may comprise a single hydraulic actuator 65 arranged on a single side wall 3 that can be actuated to press and clamp the pads 7 against the brake disc 5. In this case, the hydraulic actuator 65 may be configured as described above.

[0029] Overview of Parking Brake System 21

[0030] The brake 1 further includes a parking brake system 21. The parking brake system 21 has two electromechanical actuators 64, each arranged on one of the side walls 3, which can be actuated to block the pads 7 against the brake disc 5.

[0031] Each electromechanical actuator 64 is

[0032] a screw-nut assembly (17,18) having a rotating member (18) and a translating member (17), configured to convert rotational motion of the rotating member (18) into translational motion of the translating member (17), the screw-nut assembly (17,18) being connected within the hydraulic cylinder (10) to translate and tighten the translational member (17) relative to the piston (11) in an actuation direction (19);

[0033] an electric motor 15 constrained to the side wall 3 and connected to a power source 26 for actuating the screw-nut assemblies 17, 18;

[0034] a transmission mechanism 16 connected between the electric motor 15 and a rotating member 18;

[0035] The electromechanical actuator 64 is self-locked due to transmission irreversibility (already explained in more detail), so that when the electric motor 15 is off, the translational force of the translational member 17 cannot cause the rotational member 18 to rotate and move the translational member 17 away from the brake disc 5.

[0036] According to an alternative embodiment, for example if the caliper 2 is a so-called floating caliper, the parking brake system 21 may consist of a single electromechanical actuator 64 arranged on only one of the side walls 3 and operable to block the pads 7 against the brake disc 5. In this case, the single electromechanical actuator 64 may be configured as described above.

[0037] Description of Control System 22

[0038] The brake 1 further comprises a control system 22. The control system 22 is connected to the service brake system 20, the parking system 21 and a user interface 23. The user interface 23 comprises, for example, a service brake control interface 24 (e.g., a service pedal, a service button or a service lever) and a parking brake control interface 25 (e.g., a parking pedal, a parking button or a parking lever).

[0039] The control system 22 may comprise an electrical, electromechanical, electrohydraulic and / or electronic control system suitable for controlling the pressurization of hydraulic fluid and the operation of the electric motor 15. The control system 22 is configured and / or programmed to perform the control functions of the brake 1 in a desired manner.

[0040] According to one aspect of the present invention, in response to a parking brake user command (even in the absence of a simultaneous service brake user command), the control system 22 activates the parking brake system 21 (more precisely, the electric motor 15) in the forward direction and also activates the service brake system 20 (more precisely, the hydraulic oil supply device 13), using the service brake system 20 to move the piston 11 in the actuation direction 19 towards the brake disc 5 to a parking position where it clamps the pads 7 against the brake disc 5, and using the parking brake system 21 to lock the piston 11 in the parking position to prevent it from returning.

[0041] This allows the electric motor 15 to be dimensioned for a much lower power consumption and torque than that required to push the piston 11 along its application stroke from a retracted position away from the brake disc 5 to a long-term parking position where the brake pads 7 are clamped against the brake disc 5, because the advancement of the piston 11 and clamping of the brake disc 5 is at least partly or fully performed by the service brake system 20.

[0042] For the same reason, at least a part of the transmission mechanism 16 can be designed for mechanical stresses that are much less than the mechanical stresses required to move and clamp the piston 11 into the park brake position. With reference to the embodiment described in detail below (FIGS. 9-13), the motor pinion 55 of the electric motor 15 and the planetary reducer 58 consisting of the planet carrier plate 61, the toothed wheel 57 and the ring gear 60 can be designed for mechanical stresses that are much less than the mechanical stresses required to move and clamp the piston 11 into the park brake position.

[0043] As a result, the geometric dimensions and weight of the electromechanical actuator 64 are reduced compared to prior art solutions, particularly the axial dimensions on the outside of the vehicle, i.e., on the wheel rim side, which is necessary for implementing the invention with fixed calipers.

[0044] On the other hand, the use of hydraulic actuator 65 in conjunction with electromechanical actuator 64 during operation of brake 1 as a parking brake does not imply a need to increase the size of hydraulic actuator 65, which is necessarily already designed to apply a service brake torque that is much higher than the parking brake torque.

[0045] The electric motor 15 alone cannot release the park lock because the load and friction on the translational member is equal to the total park load and friction. Therefore, the friction at the point of no return in the transmission is very high, and the electric motor 15 is preferably not sized to overcome that friction. For this reason, in response to a user's command to release park, the control system 22: First, the hydraulic actuator 65 is activated to apply pressure to the piston 11, unloading the screw-nut assemblies 17, 18 of the electromechanical actuator 64; When the screw-nut assembly 17, 18 is unloaded (and therefore with significantly reduced friction), the electromechanical actuator 64 (motor 15 thereof) is driven to disengage the translation member 17 from the piston 11; When the translational member 17 is released from the piston 11, the hydraulic actuator 65 is activated to reduce the hydraulic pressure again and abort the parking (actual release step).

[0046] The locking of the piston 11 in the park position is released by moving the translation member 17 away from the piston 11 .

[0047] In an embodiment, in the case of a service brake user command, but in the absence of a parking brake user command, the control system actuates only the service brake system 20 without actuating the parking brake system 21 .

[0048] This allows the piston 11 to be rapidly reciprocated in order to perform service braking while the vehicle is running, without the risk of impeding the returning motion of the piston 11.

[0049] According to an embodiment, in response to a parking brake user command (even in the absence of a service brake command), control system 22:

[0050] activating the service brake system 20 (more specifically, the hydraulic fluid supply system 13), thereby moving the piston 11 in the parking direction to press the pad 7 against the brake disc 5;

[0051] only after activation of the service brake system 20, with the piston 11 already in the parking position, i.e. with the brake disc 5 already clamped, actuating the parking brake system 21 (more precisely the electric motor 15 in the forward direction), thereby translating the translational member 17 in the actuation direction 19 relative to the piston 11, locking it in the parking position and preventing its return movement;

[0052] When the piston 11 is locked in the park position, it deactivates the service brake system 20 (more precisely the hydraulic fluid supply system 13, thereby reducing the hydraulic fluid pressure) and switches off the electric motor 15.

[0053] Due to the irreversibility of the electromechanical actuator 64, the piston 11 remains locked.

[0054] This particular actuation sequence of the parking brake allows for a precise and advantageous allocation of the functions of reaching and maintaining the clamping of the brake disc 5, minimizing, or at least minimizing as much as possible, the mechanical resistance and power required by the electromechanical actuator 64.

[0055] In a particularly advantageous embodiment, the caliper 2 is a fixed caliper,

[0056] The operation of the parking brake system 21 is achieved by simultaneously operating both electric motors 15 on two opposite sides of the caliper 2.

[0057] The operation of the service brake system 20 simultaneously operates the hydraulic fluid supply systems 13 on two opposite sides of the caliper 2,

[0058] The parking brake system 21 is stopped by turning off both electric motors 15 on two opposite sides of the caliper 2,

[0059] Deactivation of the service brake system 20 deactivates the hydraulic fluid supply systems 13 on two opposite sides of the caliper 2 .

[0060] Alternatively, in an embodiment where the caliper 2 is a floating caliper, for example:

[0061] The operation of the parking brake system 21 operates the electric motor 15 on only one operating side of the caliper 2,

[0062] Activation of the service brake system 20 activates the hydraulic fluid supply system 13 on only the active side of the caliper 2;

[0063] Deactivation of the parking brake system 21 is achieved by turning off the single electric motor 15 on the only operating side of the caliper 2,

[0064] Deactivation of the service brake system 20 deactivates the hydraulic fluid supply system 13 on the only working side of the caliper 2 .

[0065] According to an embodiment (FIG. 3) which is also advantageous independently of the control system 22, the electric motor 15 of the electromechanical actuator 64 is fixed to the side wall 3 in a motor position in which the motor shaft 27 (axis of rotation of the rotor shaft) is oriented transversely, preferably perpendicularly or tangentially, but at a distance, to the intermediate axis 34 of the piston 11 which defines the aforementioned actuation direction 19. This reduces the overall dimensions of the brake 1 in the axial direction of the brake disc 5.

[0066] The motor shaft 27 advantageously abuts a gear ring 42 of the rotating member 18, which will be further described.

[0067] More advantageously, the motor shaft 27 extends on a drive surface 28 (FIG. 2) that is substantially parallel to the disc surface 29 of the brake disc 5 or that is inclined at less than 15° relative to the disc surface 29 .

[0068] Furthermore, the motor shaft 27 is inclined by less than 30°, preferably less than 20° or less than 15°, relative to a caliper plane 30 that is perpendicular to the disc plane 29 and extends between two opposing longitudinal ends 31 of the caliper 2 (FIG. 3).

[0069] The above-described position of the electric motor 15 also reduces the overall dimensions of the brake 1 in the radial direction of the brake disc 5 .

[0070] Advantageously, the two electric motors 15 on either side of the caliper 2 are arranged asymmetrically with respect to the disc plane 29 and with respect to any plane radial to the axis of rotation of the brake disc 5 (Figs. 7, 14), which makes it easier to adapt to the installation location of the wheel rim, as no internal vehicle interface changes are required.

[0071] One operating side 32 of the electric motor 15, where the electric motor 15 is connected to the transmission mechanism 16, is radially inward of the axis of rotation of the brake disc 5, while a rear side 33 of the electric motor 15 opposite the operating side 32 is radially outward of the axis of rotation of the brake disc 5. This positioning of the motor, on the one hand, leaves more space for further hydraulic cylinder-piston assemblies, and, on the other hand, allows the transmission mechanism 16 to be closer to the intermediate axis 34 of the piston 11.

[0072] Advantageously, the two electric motors 15 on two opposite sides of the caliper 2 have their working sides 32 oriented in opposite circumferential directions (relative to the axis of rotation of the brake disc 5). This also contributes to making the brake 1 more compact, especially when the central axes 34 of the two opposing pistons 11 with which the parking brake system 21 is associated are not in an intermediate position of the caliper, as shown, for example, in Figures 7 and 14.

[0073] According to a further aspect of the invention, which is advantageous independent of the positioning of the control system 22 or the electric motor 15, the translation member 17 is rotationally constrained to be integral with the caliper 2 by an anti-rotation geometric connection with a guide portion 35 which is integral with the caliper 2 and is arranged on the rear side of the translation member 17 opposite the free end 14 of the piston 11.

[0074] This eliminates the need for an anti-rotation geometric connection between the translation member 17 and the piston 11 and the associated problems of uncertainty in the translation member stroke and further axial dimensions described with reference to the prior art.

[0075] According to the embodiment (Figures 2, 4, 6), the guide part 35 protrudes from the bottom 39 of the hydraulic cylinder 10, preferably along the central axis 34 of the piston 11, and is accommodated in a corresponding guide seat 36 formed in the translation member 17 so as to be slidable, but without the possibility of relative rotation (around the central axis 34).

[0076] The anti-rotational positive connection can be achieved by complementary non-circular, for example polygonal or toothed, cross-sectional shapes of the guide portion 35 and the guide seat 36 .

[0077] Advantageously, the guide portion 35 is formed on a cylinder plug 37 (e.g., externally threaded), which can be screwed into a corresponding plug seat 38, e.g., internally threaded, of the caliper 2. By screwing the cylinder plug 37 into the plug seat 38, the hydraulic cylinder 10 can be closed to the outside of the caliper 2 and a bottom 39 of the hydraulic cylinder 10 can be formed.

[0078] According to an embodiment, the cylinder plug 37 has a substantially flat, circular base plate 52, which is preferably coaxial with the central axis 34 of the piston 11. The guide portion 35 projects from the base plate 52 towards the brake disc 5.

[0079] The planar and circular shape of the base plate 52 allows the cylinder plug 37 to be fixed, for example by screwing, in different angular positions without changing the appearance of the caliper 2 or the internal mechanical configuration of the electromechanical actuator 64.

[0080] According to an embodiment, the cylinder plug 37 supports and positions a preferably prefabricated and freestanding motion conversion assembly 40, which includes:

[0081] The cylinder plug 37 itself,

[0082] a translation member 17 rotatably integrated with the cylinder plug 37 by a non-rotatable but translatable connection with the guide portion 35;

[0083] a rotary member 18 constrained to a cylinder plug 37, preferably at a bottom 39 of the hydraulic cylinder 10, by a bearing 41 fixed to the cylinder plug 37 so as to be rotatable about a central axis 34 but constrained from translation along the central axis 34, the rotary member 18 being in threaded engagement with the translation member 17 directly or indirectly (e.g., via ball or planetary rotors);

[0084] Adjacent to the bearing 41 is a gear ring 42 formed on or fixed to the rotating member 18 .

[0085] The motion conversion assembly 40 can be easily and quickly connected to and removed from the caliper 2 in a single assembly / disassembly operation, while its individual components can be assembled and tested independently of assembly to the caliper 2.

[0086] Furthermore, as can be seen from Figures 6 and 8, the motion conversion assembly 40 configured in this manner is particularly compact both axially and radially and can therefore be easily placed within the cylinder 10-piston 11 assembly.

[0087] According to an embodiment, the guide seat 36 is manufactured separately from the translation member 17, possibly from a different material, and has a sliding bush 43 that is interference-mounted in an axial bore 44 of the translation member 17. The axial sliding and rotation-locking geometric connection between the translation member 17 and the caliper 2 takes place (exclusively) at a sliding interface 45 between the sliding bush 43 and the guide part 35.

[0088] This avoids complex machining of the rotating member 17 and allows distinguishing and optimizing the materials and sizes of the different functional parts of the motion conversion assembly 40 .

[0089] According to the embodiment (FIGS. 4, 6, 9), the bearing 41 is

[0090] an outer ring 45 defining an outer ring raceway and mounted, preferably by interference, on a bearing seat 47 of the cylinder plug 37;

[0091] a first inner half ring 48 formed integrally with the rotary member 18;

[0092] a second inner half ring 49 made separately from the first inner half ring 48 and forming an inner raceway together with the first inner half ring 48;

[0093] To connect the first and second inner half rings 48, 49 to one another, there is provided a union bushing 50 having a first end attached, preferably by interference, to the first inner half ring 48 and a second end attached, preferably by interference, to the second inner half ring 49.

[0094] This balances the need for assembly with the need for a compact mechanism.

[0095] Advantageously, the bearing seat 47 is formed by an annular wall 51 concentric with the guide part 35 and protruding from a base plate 52 of the cylinder plug 37 towards the brake disc 5 .

[0096] According to a preferred embodiment, the translation member 17 is an internal thread and the rotation member 18 is an external nut 18 of the screw-nut assembly 17,18.

[0097] The motion conversion assembly 40 can be advantageously, accurately, and simply installed by following a series of steps.

[0098] Threading the translational member (screw 17) onto the rotational member (nut 18).

[0099] Mounting the sliding bush 43 in the axial hole 44 of the translation member 17 by interference.

[0100] Attaching the ring gear 42 to the rotating member 18 by interference.

[0101] Attaching the union bushing 50 to the translation member 17 by interference.

[0102] A step of fitting the outer ring 46, rolling elements and second inner half ring 49 assembly to the union bush 50 by interference to complete the bearing 41.

[0103] Mounting the cylinder plug 37 to the outer ring 46 of the bearing 41 by interference.

[0104] A step of screwing and attaching the cylinder plug 37 to the side wall 3 of the caliper 2.

[0105] According to a further embodiment, the electric motor 15 is at least partially housed in a motor housing 53 formed integrally with the caliper 2, and advantageously no additional motor housing or casing is provided separate from and connected to the caliper 2. Instead, a support structure 55 for the motor 15 (which is inseparable from the motor 15) is screwed directly to the caliper 2.

[0106] Eliminating the separate motor housing from the caliper 2 further reduces the overall size, weight, and cost of the brake 1.

[0107] As mentioned above, the motion conversion assembly 40 or screw unit assemblies 17 , 18 are disposed coaxially with the central axis 34 of the piston 11 .

[0108] Conversely, the electric motor 15 and transmission mechanism 16 are oriented laterally or tangentially to the intermediate shaft 34 .

[0109] According to the embodiment, the transmission mechanism 16 comprises a single-stage planetary reducer 58 connected to the motor 15 and a worm screw 69 connected to the planetary reducer 58 and meshing with the ring gear 42 of the rotating member 18. The motor 15, the planetary reducer 58 and the worm screw 59 are coaxial with each other and with the motor shaft 27. This allows the overall dimensions of the brake 1 to be further reduced for the reasons already explained in connection with the positioning of the electric motor 15 only.

[0110] According to a preferred embodiment, a motor pinion 55 formed at the end of the motor shaft 56 meshes with planetary gears 57 of a planetary reducer 58, so that the motor pinion 55 forms the center pinion of the first reduction stage of the planetary reducer 58. The planetary gears 57 mesh with an internally toothed ring gear 60 that rests on the side wall 3 of the caliper 2. The planetary gears 57 are supported by satellite carrier plates 61 fixed to the worm screw 59, which in turn are rotatably supported by bearings 62 on the side wall 3 of the caliper 2. According to an embodiment in which the point of no return is achieved in the engagement area between the worm screw 59 and the ring gear 52, the electric motor 15 and the transmission from the electric motor 15 to the point of no return, i.e., to the worm screw 59, can be dimensioned only for the (reduced) stress required to move the translation member of the worm screw unit to the piston 11. The screw nut and ring gear assembly must be sized to withstand the entire parking clamp load instead, starting from the piston up to the point of no return.

[0111] The electromechanical actuator 64 is housed in a cavity 63 formed in the side wall 3 of the caliper 2 and extending from the motor housing 53 to the hydraulic cylinder 10, and a sealing gasket 67 between the cavity 63 and a sealing portion 66 of the worm gear 59 separates the internal space 12 of the hydraulic cylinder 10 from the motor housing 53 at the sealing position between the planetary reduction gear 58 and the gear zone of the worm gear 59 with the ring gear 52 of the rotating member 18.

[0112] In embodiments where two electric motors 15 are provided, said electric motors are: Independently, i.e., each motor is directly connected to the power supply, In a parallel circuit, i.e., all positive and all negative terminals are connected to each other and to a power source, They can be electrically connected in a series circuit, i.e., the negative terminal of one motor is connected to the positive terminal of the next motor.

[0113] Obviously, those skilled in the art can make further modifications and variations to the brake 1 according to the invention, all without departing from the scope of protection of the invention as defined in the following claims.

Claims

1. A hydraulic and electromechanical service and parking disc brake (1), The disc brake (1) a caliper (2) having two side walls (3) defining a disc space (4) between the two side walls for accommodating a portion of a brake disc (5); means for fixing said caliper (2) to the suspension of a vehicle; at least two pads (7) each supported by a respective one of said two side walls (3); a service brake system (20) having at least two hydraulic actuators (65) supported on each of the two side walls (3); The hydraulic actuator (65) includes a hydraulic cylinder (10) formed in the side wall (3), and a piston (11) housed in the hydraulic cylinder (10) and having a free end (14) facing the pad (7), the hydraulic cylinder (10) is in communication with a system (13) for supplying and pressurizing hydraulic fluid to apply hydraulic pressure to the piston (11) to translate the piston (11) in an actuation direction (19) towards the brake disc (5) and clamp the pads (7) against the brake disc (5); The disc brake (1) further comprises: a parking brake system (21) having at least two electromechanical actuators (64) arranged on each of said two side walls (3); The electromechanical actuator (64) has a rotating member (18) and a translational member (17), and includes a screw-nut assembly (17, 18) configured to convert rotational motion of the rotating member (18) into translational motion of the translational member (17); the screw-nut assembly (17, 18) is connected to the hydraulic cylinder (10) so as to translate and tighten the translation member (17) relative to the piston (11) in the actuation direction (19) to lock the piston (11); The electromechanical actuator (64) further comprises: an electric motor (15) connected to a power source (26) for actuating the screw-nut assembly (17, 18); a transmission mechanism (16) connected between the electric motor (15) and the rotating member (18); the at least two electromechanical actuators (64) are self-locked by the irreversibility of transmission of the at least two electromechanical actuators (64) so ​​that the translational stress of the translational member (17) cannot move the translational member (17) away from the brake disc (5) when the electric motor (15) is off; The disc brake (1) further comprises a control system (22) connected to the service brake system (20) and the parking brake system (21) and connected to a user interface (23); The translation member (17) is locked and constrained against rotation relative to the caliper (2) by an anti-rotation geometric connection with the guide portion (35); The disc brake (1), wherein the guide portion (35) is fixed to the caliper (2) and is arranged on the rear side of the translation member (17) opposite the free end (14) of the piston (11).

2. 2. The disc brake (1) according to claim 1, wherein the guide portion (35) protrudes from a bottom portion (39) of the hydraulic cylinder (10) and is accommodated in a guide seat (36) formed on the translation member (17) so as to be non-rotatable and slidable relative to the guide seat (36).

3. The guide portion (35) is formed on a cylinder plug (37) that is screwed into a plug seat (38) of the caliper (2), 3. The disc brake (1) according to claim 1 or 2, characterized in that the cylinder plug (37) closes the hydraulic cylinder (10) and forms a bottom (39) of the hydraulic cylinder (10).

4. The cylinder plug (37) supports a pre-assembled self-supporting motion conversion assembly (40); The disc brake (1) The cylinder plug (37), the translation member (17) being locked non-rotatably with respect to the cylinder plug (37) by being coupled with the guide portion (35) which is non-rotatable but translationally slidable; a bearing (41) fixed to the cylinder plug (37) at the bottom (39) of the hydraulic cylinder (10) so as to be non-slidable and non-translatable relative to the cylinder plug (37), and the rotating member (18) is threadedly engaged with the translating member (17); A disc brake (1) according to claim 3, comprising a gear ring (42) formed on the rotating member (18) adjacent to the bearing (41).

5. 5. A disc brake (1) according to any one of claims 1 to 4, wherein the electric motor (15) is fixed to the side wall (3) in a motor position in which the motor axis (27) is oriented transversely to an intermediate axis (34) of the piston (11) defining the actuation direction (19), but spaced apart from said intermediate axis (34), preferably perpendicular or tangential to said intermediate axis (34).

6. The motor shaft (27) contacts the gear ring (42) of the rotating member (18), The motor shaft (27) extends in a motor plane (28) substantially parallel to a disc surface (29) of the brake disc (5); 6. A disc brake (1) according to claim 5, wherein the motor axis (27) is inclined at an angle of less than 30°, or less than 20°, or less than 15° with respect to a caliper plane (30) that is perpendicular to the disc surface (29) and extends between two opposing longitudinal ends (31) of the caliper (2).

7. the two electric motors (15) on either side of the caliper (2) are arranged asymmetrically with respect to the disc plane (29) and with respect to any plane radial to the rotation axis of the brake disc (5); an operating side (32) of the electric motor (15) connected to the transmission mechanism (16) is located radially inward of a rear side (33) of the electric motor (15) with respect to the rotation axis of the brake disc (5); 7. The disc brake (1) according to claim 1, wherein the two electric motors (15) on either side of the caliper (2) are arranged facing each other with the operating sides (32) of the electric motors (15) facing opposite sides in the circumferential direction of the brake disc (5).

8. The electric motor (15) is at least partially housed in a motor housing (53) formed integrally with the caliper (2); 8. The disc brake (1) according to claim 1, wherein a support structure (55) for the electric motor (15), which is inseparable from the electric motor (15), is screwed directly to the caliper (2).

9. The disc brake (1) according to claim 5, wherein the transmission mechanism (16) is coaxial with the motor shaft (27).

10. The transmission mechanism (16) a planetary reducer (58) having only one reduction stage connected to the electric motor (15); A disc brake (1) according to any one of claims 1 to 9, further comprising: a worm screw (69) connected to the planetary reducer (58) and meshing with a gear ring (42) of the rotating member (18).

11. the electromechanical actuator (64) is housed in a cavity (63) formed in the side wall (3) of the caliper (2) and extending from the motor housing (53) to the hydraulic cylinder (10); 9. The disc brake (1) according to claim 8, characterized in that a sealing gasket (67) between the cavity (63) of the electromechanical actuator (64) and a sealing portion (66) hermetically separates the inner space (12) of the hydraulic cylinder (10) from the motor housing (53).

12. The caliper (2) is a fixed caliper The service brake system (20) includes two hydraulic actuators (65) disposed on the side walls (3), respectively; The disc brake (1) according to any one of claims 1 to 11, wherein the parking brake system (21) comprises the electromechanical actuators (64) arranged on each of the side walls (3).

13. In response to a user parking brake command, the control system (22) activating the service brake system (20) to move the piston (11) in the actuation direction (19) towards the brake disc (5) in a parked position where the pads (7) are clamped against the brake disc (5); 13. The disc brake (1) according to any one of claims 1 to 12, wherein the parking brake system (21) is activated to lock the piston (11) in a parking position and prevent the piston (11) from returning.

14. In response to a user's command to release the parking The control system (22) first activates the hydraulic actuator (65) to apply pressure to the piston (11) and unload the screw-nut assembly (17, 18) of the electromechanical actuator (64); When the screw-nut assembly (17, 18) is unloaded, the control system (22) activates the electromechanical actuator (64) to separate the translation member (17) from the piston (11); 14. The disc brake (1) of claim 13, wherein when the translation member (17) is separated from the piston (11), the control system (22) activates the hydraulic actuator (65) to reduce the hydraulic pressure again and release the parking brake.

15. in response to the parking brake command The control system (22) activates the service brake system (20) by moving the piston (11) to the parking position where the pad (7) is pressed against the brake disc (5); the control system (22) operates the electric motor (15) in a forward direction when the service brake system (20) is already activated and the piston (11) is in the parking position, thereby translating the translation member (17) toward the piston (11) in the actuation direction (19) to lock the piston (11) in the parking position and prevent the piston (11) from returning; When the piston (11) is locked in the parking position, the control system (22) releases the service brake system (20) by reducing hydraulic fluid pressure and turns off the electric motor (15); Disc brake (1) according to claim 13 or 14, wherein the piston (11) remains locked due to the irreversibility of the transmission of the electromechanical actuator (64).

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