Clamping device with improved release mechanism

Abstract

The invention relates to a clamping device for a braking system allowing relative displacement movement between friction elements and comprising a mechanism (15) for releasing the clamping stop comprising a disengagement wheel (17) mounted elastically and provided with partial peripheral teeth (17B) allowing, in the event of failure of the electric actuator, a release stroke of the clamping device by elastic relaxation of the disengagement wheel (17), and a device (19) for limiting the elastic relaxation of the disengagement wheel (17) in order to make the operation of the release mechanism (15) more reliable. Figure for abstract: figure 16

Description

Title of the invention: Clamping device with improved release mechanism Technical field of the invention

[0001] The invention relates to the field of vehicle braking systems, more particularly electromechanical type braking systems. Technical background

[0002] A braking system of a vehicle, in particular a motor vehicle, generally comprises mechanical clamping devices comprising in particular friction elements, such as brake pads, connected to an actuator capable of bringing a pair of these friction elements together in the direction of two opposite faces of a disc secured to a wheel of the vehicle to grip it and thus brake the vehicle by friction of the friction elements against the disc, or of moving them apart in order to stop braking.

[0003] In the case of electromechanical type braking systems, the mechanical clamping devices comprise at least one electrical actuator such as an electric motor. However, in the event of an electrical failure, the electromechanical type braking system may, under certain circumstances, continue to apply a braking force so that it is no longer possible to move the vehicle.

[0004] In addition, mechanical braking devices must perfectly adapt to the progressive wear of the brake pads to ensure effective braking but also provide an operation allowing the brake pads to be changed. All these constraints are difficult to meet at the same time without adding dedicated mechanisms. Summary of the invention

[0005] The invention aims in particular to propose a tightening device of the electromechanical type adapting to the wear of the friction elements, which is mechanically capable of automatically and reliably releasing any braking tightening, in particular in the event of an electrical failure, and which offers simplified maintenance, in particular when changing the friction elements, in a very compact volume with regard to all these integrated functions.

[0006] To this end, the invention relates to a clamping device for a braking system intended to exert a relative movement between friction elements and comprising a frame supporting an electric actuator intended to provide a clamping force to a clamping stop using a transmission gear in order to allow the relative movement between the friction elements, characterized in that the clamping device further comprises a mechanism for releasing the clamping stop. comprising a disengagement wheel mounted to rotate elastically on the frame and provided with partial peripheral teeth intended to be coupled to the transmission gear allowing, in the event of failure of the electric actuator, a release stroke of the clamping device by driving the transmission gear thanks to the elastic relaxation of the disengagement wheel, and in that the release mechanism comprises a device for limiting the elastic relaxation of the disengagement wheel in order to make the operation of the release mechanism more reliable.

[0007] Advantageously according to the invention, during normal use of the clamping device, the release mechanism consumes mechanical energy from the transmission gear to elastically move the disengagement wheel (elastic contraction) when the clamping stop is released (activation of braking) and restores it to the transmission gear when the clamping stop is retracted (deactivation of braking). There is therefore ultimately no significant difference apart from the addition of the release mechanism. The clamping device can therefore maintain effective and uniform braking regardless of the wear of the friction elements.

[0008] During an intervention to change the friction elements or in the event of an electrical failure, the release mechanism, whatever the output position of the clamping stop, is advantageously capable, according to the invention, of automatically and mechanically retracting (no need for electrical energy) the clamping stop by elastic displacement of the disengagement wheel (elastic detent) to drive the assembly autonomously, i.e. in particular the transmission gear and the deactivated electrical actuator. Thus, in the event of an intervention to change the friction elements, the technician does not have to force the two friction elements apart, as is currently the case with hydraulic systems; the friction elements according to the invention will be automatically released, in whole or in part, from their rest position depending on the wear that required a change.Finally, in the event of an electrical failure, generally linked to an accident, the friction elements according to the invention during the braking phase will be automatically released to allow the vehicle to be moved.

[0009] Furthermore, the advantage of the partial peripheral toothing makes it possible to limit the size of the release mechanism by having a first end for actuating the partial toothing (maximum elastic contraction of the disengagement wheel by the transmission gear) and a second end for releasing the partial toothing (maximum elastic relaxation of the disengagement wheel against the transmission gear) in order to use each direction of rotation of the disengagement wheel according to predetermined angles respectively in absorption of mechanical energy (elastic recharging of the release mechanism) and in restitution of mechanical energy (elastic unloading of the release mechanism) according to an angle partial toothing at least less than 270 degrees because the actuation stroke of the clamping stop will always be the same regardless of the wear of the friction elements. In addition, the partial toothing makes it possible to compensate for this wear of the friction elements as explained below.

[0010] Finally, the limiting device advantageously avoids, according to the invention, the accidental meshing of the first actuating end of the partial toothing with the transmission gear during a possible disproportionate elastic relaxation of the disengagement wheel. It is understood that the disengagement wheel cannot be de-indexed and that the release mechanism is more reliable.

[0011] The invention alternatively comprises one or more of the following optional features, taken alone or in combination.

[0012] The disengagement wheel comprises a recess capable of forming said partial peripheral toothing so as to drive, upon activation of the clamping device, the disengagement wheel, by the transmission gear train, according to a maximum negative rotation of between 160 degrees and 200 degrees between an inactive position (such as the rest position) of the clamping device to an active position of the clamping device corresponding to the actuation stroke of the clamping stop which is close between two braking operations. It is therefore understood that the partial toothing makes it possible to use the absorption only over a drive range determined by the transmission gear train, i.e. up to the first actuation end of the partial toothing corresponding to a predetermined actuation stroke of the clamping stop.As the friction elements wear, the movement of the transmission gear will periodically exceed that of the actuating end of the partial toothing, causing a relative elastic movement between the disengagement wheel (in elastic contraction) and the transmission gear. It is therefore understood that the release mechanism adapts, advantageously according to the invention, to the travel of the clamping stop as a function of the wear of the friction elements.

[0013] The disengagement wheel is mounted elastically on the frame using at least one elastic element mounted between the disengagement wheel and the frame so as to exert, upon activation of the clamping device, a contraction of said at least one elastic element up to an actuating end of the partial toothing. It is therefore understood that the first actuating end is held elastically against the transmission gear by relaxation of said at least one elastic element in particular to compensate for the relative elastic displacement between the disengagement wheel (in elastic contraction) and the transmission gear due to wear of the friction elements.

[0014] Said at least one elastic element is wound around the axis of rotation between the disengagement wheel and the frame so as to, in the event of an electrical failure of the clamping device, generate a relaxation of said at least one elastic element in a direction capable of driving in particular the rotations of the disengagement wheel and the transmission gear train in order to induce said release stroke of the clamping device. Such a spiral-type arrangement of said at least one elastic element makes it possible to impose an angular effect, more particularly, a rotary constraint on the disengagement wheel.

[0015] The device for limiting the elastic relaxation of the disengagement wheel comprises a stop element intended to define a disengagement position of a second release end of the partial toothing according to a maximum positive rotation of between 70 degrees and 110 degrees relative to an inactive position (such as the rest position) of the clamping device in order to avoid the meshing of the other end of the partial toothing with the transmission gear during the elastic relaxation of the disengagement wheel. Indeed, this capping of the movement of the disengagement wheel makes it possible to make its movement reliable in the various acceleration situations (positive or negative) that a vehicle may encounter. Advantageously according to the invention, the stop element may be of different geometries and / or locations such as, for example, mounted on the frame of the clamping device or on the disengagement wheel of the release mechanism.

[0016] Furthermore, the stop element cooperates, preferably, with at least one flexible element so that the second release end of the partial toothing is held elastically against the transmission gear by relaxation of said at least one flexible element in order to adapt to the travel of the clamping stop, in particular when changing the friction elements. Here again, advantageously according to the invention, in the event of a change of the friction elements or in the event of an electrical failure, it is not necessary to re-engage the disengagement wheel with the transmission gear, and the release mechanism is automatically recalibrated at the first braking to the travel of the clamping stop as explained above.

[0017] The invention also relates to a vehicle braking system comprising a pair of friction elements intended to cooperate by friction with a disc, characterized in that it comprises a clamping device as presented above arranged to bring the pair of friction elements towards two opposite faces of the disc in order to clamp it.

[0018] Finally, the invention relates to a vehicle characterized in that it comprises a braking system as presented above. Brief description of the figures

[0019] Other features and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended drawings, in which:

[0020] [Fig-1] is a schematic top view of an example of a vehicle in which a braking system according to the invention is mounted;

[0021] [Fig.2] is a schematic view of an example of a braking system according to the invention;

[0022] [Fig.3] is a partial perspective view of an exemplary clamping device according to the invention;

[0023] [Fig.4] is a partial front view of the example of a clamping device according to the invention;

[0024] [Fig.5] is a partial perspective view of an exemplary release mechanism according to the invention;

[0025] [Fig.6] to [Fig.8] are partial front views of successive stages of activation of the clamping device and the example release mechanism according to the invention;

[0026] [Fig.9] and [Fig. 10] are partial front views of successive stages of release of the clamping device and of the example of a release mechanism according to the invention;

[0027] [Fig. 11] is a partial front view of a release mechanism according to a first embodiment of the invention;

[0028] [Fig. 12] is a partial sectional view of a release mechanism according to a second embodiment of the invention;

[0029] [Fig. 13] is a partial front view of the release mechanism according to the second embodiment of the invention;

[0030] [Fig. 14] is a partial side view of a release mechanism according to a third embodiment of the invention according to a release movement of the disengagement wheel;

[0031] [Fig. 15] is a partial side view of the release mechanism according to the third embodiment of the invention according to an actuation movement of the disengagement wheel;

[0032] [Fig. 16] is a partial front view of the release mechanism according to the third embodiment of the invention. Detailed description

[0033] In the various figures, identical or similar elements bear the same references, possibly with the addition of an index. The description of their structure and function is therefore not systematically repeated.

[0034] In all that follows, the orientations are the orientations of the figures. In particular, the terms “upper”, “lower”, “left”, “right”, “above”, "below", "forward" and "backward" are generally understood in relation to the direction in which the figures are represented. However, a further distinction is made between:

[0035] - an axial direction A, coincident with the central axis of the clamping stop 11;

[0036] - a radial direction R, perpendicular to the axial direction A, passing through the diameter in the median plane of disc 3; and

[0037] - a tangential direction T, perpendicular to the axial direction A, resulting from the friction by friction elements 2a, 2b moving towards each other in the axial direction A pressing against the disc 3 rotating in an axis parallel to the axial direction A and secured to a wheel 5 of a vehicle 4.

[0038] The invention applies to any type of braking system 1, in particular those intended to equip motor vehicles 4 of the passenger car type, SUV (“Sport Utility Vehicles”), two-wheelers (in particular motorcycles), airplanes, industrial vehicles chosen from vans, “Heavy Goods Vehicles” - i.e. metro, bus, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles -, or other transport or handling vehicles. The invention also applies to non-motorized vehicles such as in particular a trailer, a semi-trailer or a caravan.

[0039] By "electromechanical type braking system 1" is meant all types of braking systems 1 (four in [Fig.l]) comprising at least one electric actuator 12 intended to bring friction elements 2a, 2b together in order to laterally pinch a disc 3 secured to a wheel 5 of vehicle 4 to brake it.

[0040] In the explanation below, there is talk of positive rotation or negative rotation in particular of the disengagement wheel 17. This does not mean that said rotations are necessarily respectively trigonometric and anti-trigonometric directions but simply that the rotations are in opposite directions, that is to say respectively a first direction of rotation for deactivating the clamping device 7 (or for releasing by the releasing mechanism 15) and the other second direction of rotation for activating the clamping device 7 (or for actuating the releasing mechanism 15).

[0041] In the examples of Figures 2 and 3, a braking system 1 with a clamping device 7 of the floating caliper type is used, making it possible to limit the number of electric actuators and thus to be more compact. The clamping device 7 is formed of a frame 8 comprising an electric actuator 12 on one side only and is formed of a yoke 9 fixed relative to the vehicle 4 and a caliper 10 movable relative to the yoke 9 arranged to bring the friction element 2b closer once the friction element 2a is in contact with the disc 3. Such a clamping device 7 of the floating caliper type makes it possible to use fewer electric actuators 12 and thus to be more compact. In a manner known per se, the clamping device 7 comprises a control unit intended to manage each electric actuator 12 to provide the desired clamping force and all associated power and control devices in order in particular to manage the amplitude and the force of bringing together the friction elements 2a, 2b.

[0042] Of course, the invention also applies to a braking system 1 with a clamping device 7 of the fixed caliper type, that is to say that a frame 8, formed of a caliper 10 fixed relative to the vehicle 4, comprises at least one electric actuator 12 for each element 2a, 2b on each side of the disc 3 to bring the friction elements 2a, 2b together respectively in order to come into contact with the disc 3.

[0043] The clamping device 7 is intended to exert a relative movement between friction elements 2a, 2b by movement in the axial direction A of a clamping stop 11. More precisely, the electric actuator 12 is connected at its output shaft 13 to a transmission gear 14 in order to allow the translational movement in the axial direction A of the clamping stop 11 and, incidentally, the movement of bringing together the friction elements 2a, 2b allowing braking or, conversely, the movement of separating the friction elements 2a, 2b allowing the braking to be released.

[0044] Advantageously according to the invention, the clamping device 7 comprises a mechanism 15 for releasing the clamping stop 11 allowing, for example in the event of failure of the electric actuator 12, a release stroke of the clamping device 7 which is in particular mechanically capable of automatically and reliably releasing any braking applied by the clamping stop 11. In the examples illustrated in FIGS. 3 to 16, the release mechanism 15 is coupled to the transmission gear train 14 in a manner opposite to the mounting of the electric actuator 12. This layout is preferred for distributing the members substantially horizontally in the casing 15A of the frame 8.

[0045] Of course, a different configuration is possible to adapt a different frame geometry without departing from the scope of the invention. The transmission gear 14 must simply be able to be driven by both the electric actuator 12 and the release mechanism 15 to remain within the disclosure of the invention.

[0046] According to the invention, the release mechanism 15 mainly comprises a disengagement wheel 17 and a limiting device 19. Advantageously according to the invention, the disengagement wheel 17 is mounted elastically rotatably on the frame 8 by means of the pivot shaft 17D around the rotation axis B passing through the center of the pivot shaft 17D. In addition, the disengagement wheel 17 is provided with partial peripheral teeth 17B intended to be coupled to the transmission gear train 14 as, for example, illustrated in the example of [Fig. 4]. As explained below, depending on the operation of the release mechanism 15, the disengagement wheel 17 may, temporarily or occasionally, no longer be coupled to the transmission gear 14 in particular because of its elastic mounting relative to the frame 8.

[0047] In the examples illustrated in Figures 3 to 16, the disengagement wheel 17 is mounted to rotate elastically on the frame 8 using at least one elastic element 15B mounted between the disengagement wheel 17 and the frame 8 so as to exert, upon activation of the clamping device 7, a contraction of said at least one elastic element up to an actuating end EA of the partial peripheral toothing 17B as illustrated in the example of [Fig.8]. It is therefore understood that the first actuating end EA is held elastically against the transmission gear 14 by relaxation of said at least one elastic element 15B in particular to compensate for any relative elastic displacement between the disengagement wheel 17 (in elastic contraction) and the transmission gear 14 due to wear of the friction elements 2a, 2b.

[0048] As better visible in the example of [Fig. 5], said at least one elastic element 15B is preferentially wound around the axis B of rotation between the disengagement wheel 17 (a first end of the element 15B is attached to the lower level of the disengagement wheel 17) and the frame 8 (a second end of the element 15B is attached to the internal level of the casing 15A of the frame 8) so as, in the event of an electrical failure of the clamping device, to generate a relaxation of said at least one elastic element 15B in a direction capable of causing in particular both the negative rotation of the disengagement wheel 17 and the positive rotation of the transmission gear 14 in order to induce said release stroke of the clamping device 7 and, more precisely, the retracting movement of the clamping stop 11. Such a spiral arrangement of said at least one elastic element 15B makes it possible to impose a rotational constraint on the disengagement wheel 17.

[0049] It is therefore understood, in particular in the event of failure of the electric actuator 12, that a release stroke of the clamping device 7 by driving the transmission gear train 14 is obtained by the sole elastic relaxation of the disengagement wheel 17. Advantageously according to the invention, during normal use of the clamping device 7, the release mechanism 15 consumes mechanical energy from the transmission gear train 14 to elastically move the disengagement wheel 17 (elastic contraction) when the clamping stop 11 comes out (activation of braking) and restores it to the transmission gear train 14 when the clamping stop 11 is retracted (deactivation of braking). There is therefore ultimately no notable difference apart from the addition of the release mechanism 15. The clamping device 7 can therefore maintain effective and uniform braking regardless of the wear of the friction elements 2a, 2b.

[0050] As seen in the examples of Figures 3 to 16, the disengagement wheel 17 comprises a recess 17C (in the form of a disc arc in figures 3 to 16) capable of forming said partial peripheral toothing 17B. The recess 17C imposes an interruption of the partial peripheral toothing 17B of between 70 degrees and 110 degrees, that is to say, for example, equal to 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees or 110 degrees.

[0051] Of course, another form of recess 17C and more generally another form of disengagement wheel 17 can be envisaged without departing from the scope of the invention. Thus, a star of which one (or more) branches can be shortened also makes it possible to form a disengagement wheel 17 with a partial peripheral toothing 17B without departing from the scope of the invention.

[0052] Advantageously according to the invention, the partial peripheral toothing 17B makes it possible to limit the size of the release mechanism 15 by having a first end EA for actuating the partial peripheral toothing 17B (maximum elastic contraction of the disengagement wheel 17 by the transmission gear 14) and a second end EL for releasing the partial peripheral toothing 17B (maximum elastic relaxation of the disengagement wheel 17 against the transmission gear 14) in order to use each direction of rotation of the disengagement wheel 17 according to predetermined angles respectively in absorption of mechanical energy (elastic recharging of the release mechanism 15) and in restitution of mechanical energy (elastic unloading of the release mechanism 15) according to a partial toothing angle preferably at least less than 270 degrees.Indeed, the actuation stroke of the clamping stop 11 will always be close regardless of the wear of the friction elements 2a, 2b; only the inactive position, such as the rest position, of the clamping device 7 is readjusted at the end of each braking depending on the wear. Thus, the partial toothing also makes it possible to compensate for this wear of the friction elements 2a, 2b as explained below.

[0053] Advantageously according to the invention, as visible in the example of figures 6 to 8, the partial peripheral toothing 17B is formed so as to drive, during activation of the clamping device 7, the disengagement wheel 17, by the transmission gear train 14, according to a predetermined maximum negative rotation between an inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6] towards an active position of the clamping device 7 illustrated in [Fig.8] corresponding to an actuation stroke of the clamping stop 11 which is close between two braking operations.

[0054] According to an example illustrated in Figures 6 to 8, said predetermined negative maximum rotation may be between 160 degrees and 200 degrees, that is, for example, equal to 160 degrees, 165 degrees, 170 degrees, 175 degrees, 180 degrees, 185 degrees, 190 degrees, 195 degrees or 200 degrees between the inactive position, such as the position of rest, of the clamping device 7 illustrated in [Fig.6] towards the active position of the clamping device 7 illustrated in [Fig.8]. It is therefore understood that the partial peripheral toothing 17B makes it possible to use the absorption only over a drive range determined by the transmission gear 14, i.e. up to the first actuating end EA of the partial peripheral toothing 17B corresponding to a predetermined activation stroke of the clamping stop 11. As the friction elements wear, the displacement of the transmission gear 14 will periodically exceed that of the actuating end EA of the partial peripheral toothing 17B causing a relative elastic displacement between the disengagement wheel 17 (in elastic contraction) and the transmission gear 14.It is therefore understood that the release mechanism 15 “recalibrates”, advantageously according to the invention, to the travel of the clamping stop 11 as a function of the wear of the friction elements 2a, 2b so that the rest angle of the disengagement wheel 17 repositions itself to the inactive position, such as the effective rest position of the clamping device 7 as illustrated in [Fig.6].

[0055] Consequently, in particular during an intervention to change the friction elements 2a, 2b or in the event of an electrical failure (for example the electric actuator 12 is no longer supplied with electrical energy), the release mechanism 15, whatever the output position of the clamping stop 11, is advantageously capable, according to the invention, of automatically and mechanically retracting (no need for electrical energy) the clamping stop 11 by elastic displacement of the disengagement wheel 17 (elastic relaxation) to drive the assembly autonomously, that is to say in particular the transmission gear 14 and the deactivated electric actuator 12.Thus, in the event of an intervention to change the friction elements, the technician does not have to forcefully separate the two friction elements 2a, 2b, as is currently the case with hydraulic systems; the friction elements 2a, 2b according to the invention will automatically be fully or partially released from their inactive position, such as the rest position, depending on the wear that required a change. Finally, in the event of an electrical failure, generally linked to an accident, the friction elements 2a, 2b according to the invention during the braking phase will be automatically released to allow the vehicle to be moved.

[0056] Advantageously according to the invention, the release mechanism 15 also comprises a device 19 for limiting the elastic relaxation of the disengagement wheel 17 in order to make the operation of the release mechanism 15 more reliable. Several embodiments are described below. However, for all the embodiments, the limitation device 19 comprises a stop element 19A intended to define a disengagement position of the second end EL for releasing the partial peripheral toothing 17B which, as will be explained in the embodiments The realization below may vary.

[0057] According to the invention, the disengagement position of the second end EL for releasing the partial peripheral toothing 17B is obtained by a maximum positive rotation of between 70 degrees and 110 degrees relative to the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6], that is to say, for example, equal to 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees or 110 degrees.

[0058] The purpose of the limiting device 19 is to limit, or even elastically cancel, the gap I (visible in [Fig. 10]) between the second end EL for releasing the partial peripheral toothing 17B and the transmission gear 14. In addition, this is to prevent the actuating end EA of the partial peripheral toothing 17B from meshing with the transmission gear 14 during the elastic relaxation of the disengagement wheel 17 during a possible disproportionate elastic relaxation of the disengagement wheel 17. The disengagement wheel 17 advantageously remains correctly indexed to the transmission gear 14. Thus, this capping of the movement of the disengagement wheel 17 makes it possible to make its movement reliable in the various acceleration situations (positive or negative) that a vehicle 4 may encounter.

[0059] Advantageously according to the invention, the stopper element 19A can be of different geometries and / or locations such as, for example, mounted on the frame 8 of the clamping device 7 or on the disengagement wheel 17 of the release mechanism 15.

[0060] Furthermore, the stop element 19A cooperates, preferably, with at least one flexible element 19B so that the second end EL for releasing the partial peripheral toothing 17B is held elastically against the transmission gear 14 by relaxation of said at least one flexible element 19B in order to adapt to the travel of the clamping stop 11, in particular when changing the friction elements. Here again, advantageously according to the invention, in the event of a change of the friction elements or in the event of an electrical failure, it is not necessary to re-enter the disengagement wheel 17 with the transmission gear 14, and the release mechanism 15 is automatically recalibrated at the first braking to the travel of the clamping stop 11 as explained above.

[0061] According to a first embodiment illustrated in [Fig. 11], the stop element 19A is fixedly mounted at the internal level of the casing 15A of the frame 8. The stop element 19A cooperates with at least one flexible element 19B via a limiting element 17E, both mounted on the disengagement wheel 17. In this first embodiment, the limiting device 19 makes it possible to elastically cancel the gap I (elastic take-up) between the second end EL for releasing the partial peripheral toothing 17B and the transmission gear 14. More precisely, that the activation of the stop 11 of clamping induces the position of the example of [Fig.7] or 8, if an electrical failure occurs (for example the electric actuator 12 is no longer supplied with electrical energy), the disengagement wheel 17 will elastically relax and exceed the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6] to arrive at that of [Fig.9] in which the stopper element 19A comes into contact with the limiting element 17E. The disengagement wheel 17 continues its movement by contracting said at least one flexible element 19B until the disengagement wheel 17 reaches its position illustrated in [Fig. 10]. At this moment, said at least one flexible element 19B by elastic relaxation imposes a reverse rotation on the disengagement wheel 17 until the second end EL for releasing the partial peripheral toothing 17B comes into contact with the transmission gear 14.The partial peripheral toothing 17B being held elastically meshed with the transmission gear 14, it is understood that the release mechanism 15 is automatically recalibrated at the first braking to the travel of the clamping stop 11 as explained above.

[0062] According to a second embodiment illustrated in [Fig. 12] and 13, the stopper element 19A is fixedly mounted on the disengagement wheel 17. The stopper element 19A cooperates with at least one flexible element 19B mounted at the internal level of the casing 15A of the frame 8. In this second embodiment, the limiting device 19 makes it possible to elastically cancel the gap I (elastic take-up) between the second end EL for releasing the partial peripheral toothing 17B and the transmission gear 14. More precisely, whether the activation of the clamping stop 11 induces the position of the example of [Fig.7] or 8, if an electrical failure occurs (for example the electric actuator 12 is no longer supplied with electrical energy), the disengagement wheel 17 will elastically relax and exceed the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6] to arrive at that of [Fig.9] in which the stopper element 19A comes into contact with said at least one flexible element 19B. The disengagement wheel 17 continues its movement by contracting said at least one flexible element 19B until the disengagement wheel 17 reaches its position illustrated in [Fig. 10]. At this moment, said at least one flexible element 19B by elastic relaxation imposes a reverse rotation on the disengagement wheel 17 until the second end EL for releasing the partial peripheral toothing 17B comes into contact with the transmission gear 14 as illustrated in [Fig. 13]. The partial peripheral toothing 17B being held elastically meshed with the transmission gear 14, it is understood that the release mechanism 15 is automatically recalibrated at the first braking to the stroke of the clamping stop 11 as explained above.

[0063] According to a third embodiment illustrated in figures 14 to 16, the element 19A stopper is fixedly mounted at the internal level of the casing 15A of the frame 8. The stopper element 19A essentially comprises a fixed part 19A1 mounted at the internal level of the casing 15A of the frame 8 and a part 19A2 forming a rocker pivotally mounted on the fixed part 19A1 at the level of the axis O. In this third embodiment, the limiting device 19 makes it possible to limit the gap I (elastic take-up) between the second end EL for releasing the partial peripheral toothing 17B and the transmission gear 14. More specifically, whether the activation of the clamping stop 11 induces the position of the example of [Fig.7] or 8, if an electrical failure occurs (for example the electric actuator 12 is no longer supplied with electrical energy), the disengagement wheel 17 will elastically relax and exceed the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6].The disengagement wheel 17 continues its movement until the disengagement wheel 17 reaches its position illustrated in [Fig. 16]. At this time, the disengagement wheel 17 comes into contact with the rocker-forming part 19A2 and forces it to stop in a position where the second release end EL of the partial peripheral toothing 17B is no longer in contact with the transmission gear 14 as illustrated in [Fig. 16] but is reasonably close. In order to make the release mechanism 15 functional again, the disengagement wheel 17 must be re-engaged, the release mechanism 15 is then automatically recalibrated at the first braking to the stroke of the clamping stop 11 as explained above. As seen in [Fig. 15], in the direction of rotation of the braking, the disengagement wheel 17 is not prevented from passing the stopper element 19A by pivoting of the part 19A2 forming a rocker.

[0064] In order to limit the risk of the rocker-forming part 19A2 buckling against the disengagement wheel 17, the limitation device 19 preferably comprises a pivoting roller 19A3 mounted at the end of the rocker-forming part 19A2 opposite the axis O and intended to roll on the disengagement wheel 17 in order to reduce, or even eliminate, the coefficient of friction between the two parts.

[0065] The invention is not limited to the embodiments and variants presented and other embodiments and variants will become clear to those skilled in the art. Thus, the embodiments and variants can be combined with each other without departing from the scope of the invention. By way of non-limiting example, it is possible to mix a stopper element 19A of one embodiment with at least one flexible element 19B of another embodiment without departing from the scope of the invention. List of references

[0066] 1 - braking system 2a - friction element 2b - friction element 3 - disc 4 - vehicle 5 - wheel 7 - clamping device 8 - built 9 - screed 10 - stirrup 11 - clamping stop 12 - electric actuator 13 - output shaft 14 - transmission gear 15 - release mechanism 15A - crankcase 15B - elastic element 17 - disengagement wheel 17 A - board 17B - partial peripheral dentition 17C - recess 17D - pivot shaft 17E - limiting element 19 - device for limiting the elastic relaxation of the disengagement wheel 19A - stopper element 19A1 - fixed part of the stop element 19A2 - rocker part of the stop element 19A3 - pivoting roller of the stopper element 19B - flexible element A - axial direction B - axis of rotation of the disengagement wheel I - gap between the second release end of the partial peripheral toothing and the transmission gear O - axis of rotation of the stopper element R - radial direction T - tangential direction EA - first actuating end of the partial toothing EL - second partial denture release end

Claims

Claims

1. Clamping device (7) for a braking system (1) intended to exert a relative displacement between friction elements (2a, 2b) and comprising a frame (8) supporting an electric actuator (12) intended to provide a clamping force to a clamping stop (11) using a transmission gear (14) in order to allow the relative displacement movement between the friction elements (2a, 2b), characterized in that the clamping device (7) further comprises a mechanism (15) for releasing the clamping stop (11) comprising a disengagement wheel (17) mounted elastically rotatably on the frame (8) and provided with partial peripheral teeth (17B) intended to be coupled to the transmission gear (14) allowing, in the event of failure of the electric actuator (12), a release stroke of the clamping device (7) by driving the transmission gear (14) thanks to the elastic relaxation of the disengagement wheel (17),and in that the release mechanism (15) comprises a device (19) for limiting the elastic relaxation of the disengagement wheel (17) in order to make the operation of the release mechanism (15) more reliable.

2. Clamping device (7) according to the preceding claim, in which the disengagement wheel (17) comprises a recess (17C) capable of forming said partial peripheral toothing (17B) so as to drive, upon activation of the clamping device (7), the release wheel (17), by the transmission gear (14), according to a maximum negative rotation of between 160 degrees and 200 degrees between an inactive position of the clamping device (7) towards an active position of the clamping device (7) in order to adapt to the travel of the clamping stop (11) depending on the wear of the friction elements (2a, 2b).

3. Clamping device (7) according to claim 1 or 2, wherein the disengagement wheel (17) is elastically rotatably mounted on the frame (8) using at least one elastic element (15B) mounted between the disengagement wheel (17) and the frame (8) so as to exert, upon activation of the clamping device (7), a contraction of said at least one elastic element (15B) up to an actuating end of the partial toothing (17B), which is held elastically against the transmission gear (14) by relaxation of said at least one elastic element (15B).

4. Clamping device (7) according to the preceding claim, in which

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11. said at least one elastic element (15B) is wound around the axis (B) of rotation between the disengagement wheel (17) and the frame (8) so as to, in the event of an electrical failure of the clamping device (7), generate a relaxation of said at least one elastic element (15B) in a direction capable of driving the rotations of the disengagement wheel (17) and the transmission gear (14) in order to induce said release stroke of the clamping device (7). Clamping device (7) according to any one of the preceding claims, in which the device (19) for limiting the elastic relaxation of the disengagement wheel (17) comprises a stop element (19A) intended to define a disengagement position of one end (EL) for releasing the partial toothing (17B) according to a maximum positive rotation of between 70 degrees and 110 degrees relative to an inactive position of the device (7) in order to avoid the meshing of the other end of the partial toothing (17B) with the transmission gear (14) during the elastic relaxation of the disengagement wheel (17). Clamping device (7) according to the preceding claim, in which the stop element (19A) cooperates with at least one flexible element (19B) so that the release end (EL) of the partial toothing (17B) is held elastically against the transmission gear (14) by relaxation of said at least one flexible element (19B) in order to adapt to the travel of the clamping stop (11), in particular when changing the friction elements (2a, 2b). Clamping device (7) according to claim 5 or 6, in which the stop element (19A) is mounted on the frame (8). Clamping device (7) according to claim 5 or 6, wherein the stop element (19A) is mounted on the disengagement wheel (17). Clamping device (7) according to any one of the preceding claims, being of the floating stirrup type. Braking system (1) for a vehicle comprising a pair of friction elements (2a, 2b) intended to cooperate by friction with a disc (3), characterized in that it comprises a clamping device (7) according to any one of the preceding claims for bringing the pair of friction elements (2a, 2b) towards two opposite faces of the disc (3) in order to clamp it. Vehicle (4) characterized in that it comprises at least one braking system (1) according to the preceding claim.

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