Clamping device with improved release mechanism

Abstract

The invention relates to a clamping device for a braking system that allows relative movement between friction elements and includes a clamping stop release mechanism (15) comprising an elastically mounted disengagement wheel (17) with partial peripheral teeth (17B) allowing, in the event of an electric actuator failure, a release stroke of the clamping device by elastic extension of the disengagement wheel (17), and a device (19) for limiting the elastic extension of the disengagement wheel (17) in order to ensure the reliable operation of the release mechanism (15). Figure 16 (for the abstract)

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 to electromechanical braking systems. Technical background

[0002] A braking system of a vehicle, in particular a motor vehicle, generally includes 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 towards two opposite faces of a disc attached to a wheel of the vehicle in order to clamp 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 braking systems, the mechanical clamping devices include at least one electric actuator such as an electric motor. However, in the event of an electrical failure, the electromechanical braking system may, under certain circumstances, continue to apply a braking force such that it is no longer possible to move the vehicle.

[0004] Furthermore, the mechanical braking devices must adapt perfectly to the progressive wear of the brake pads to ensure effective braking, but also provide a mechanism for changing the brake pads. All these constraints are difficult to meet simultaneously without adding dedicated mechanisms. Summary of the invention

[0005] The invention aims in particular to provide an electromechanical clamping device that adapts to the wear of the friction elements, which is mechanically capable of automatically and reliably releasing any braking clamping, particularly in the event of an electrical failure, and which offers simplified maintenance, particularly when changing the friction elements, in a very compact volume considering all these integrated functions.

[0006] To this end, the invention relates to a clamping device for a braking system intended to exert a relative displacement between friction elements and comprising a frame supporting an electric actuator intended to provide a clamping force to a clamping stop by means of a transmission gear in order to allow the relative displacement 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 having a partial peripheral toothing 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 release of the disengagement wheel, and in that the release mechanism includes a device for limiting the elastic release 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 (braking activation), and returns this energy to the transmission gear when the clamping stop is retracted (braking deactivation). Therefore, there is ultimately no significant difference other than the addition of the release mechanism. The clamping device can thus maintain effective and consistent braking regardless of the wear of the friction elements.

[0008] During a friction element replacement operation or in the event of an electrical failure, the release mechanism, regardless of the clamping stop's extension position, is advantageously capable, according to the invention, of automatically and mechanically retracting the clamping stop (no electrical power required) by elastic displacement of the disengagement wheel (elastic release) to autonomously drive the assembly, i.e., in particular, the transmission gear and the deactivated electric actuator. Thus, in the event of a friction element replacement operation, the technician does not have to forcibly separate the two friction elements, as is currently the case with hydraulic systems; the friction elements according to the invention will be automatically released, wholly or partially, from their rest position depending on the wear that necessitated replacement.Finally, in the event of an electrical failure, generally related to an accident, the friction elements according to the invention during braking will be automatically released to allow the vehicle to be moved.

[0009] Furthermore, the advantage of the partial peripheral teeth is that it limits the size of the release mechanism by presenting a first actuating end of the partial teeth (maximum elastic contraction of the disengagement wheel by the transmission gear) and a second releasing end of the partial teeth (maximum elastic relaxation of the disengagement wheel against the transmission gear) in order to utilize each direction of rotation of the disengagement wheel at predetermined angles respectively in absorption of mechanical energy (elastic recharging of the release mechanism) and in release of mechanical energy (elastic unloading of the release mechanism) at an angle The partial tooth pitch must be at least 270 degrees, as the actuation stroke of the clamping stop will always be the same regardless of wear on the friction elements. Furthermore, the partial tooth pitch compensates for this wear on the friction elements, as explained below.

[0010] Finally, the limiting device advantageously prevents, according to the invention, the accidental engagement of the first actuating end of the partial gear teeth with the transmission gear during a possible disproportionate elastic release of the disengagement wheel. It is understood that the disengagement wheel cannot be disindexed and that the release mechanism is thus made more reliable.

[0011] The invention includes, as an alternative, one or more of the following optional features, taken alone or in combination.

[0012] The disengagement wheel has a recess adapted to form said partial peripheral teeth so as to drive, when the clamping device is activated, the release wheel, by the transmission gear, through a maximum negative rotation of between 160 degrees and 200 degrees between an inactive position (such as the rest position) of the clamping device and 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 teeth allow the absorption to be used only over a drive range determined by the transmission gear, that is to say, up to the first actuation end of the partial teeth corresponding to a predetermined actuation stroke of the clamping stop.As the friction elements wear, the displacement of the transmission gear will periodically exceed that of the actuating end of the partial teeth, resulting in a relative elastic displacement between the disengagement wheel (under elastic contraction) and the transmission gear. It is therefore understood that the release mechanism, advantageously according to the invention, adapts to the stroke of the clamping stop as a function of the wear of the friction elements.

[0013] The disengagement wheel is elastically mounted on the frame by means of 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 teeth. It is therefore understood that the first actuating end is held elastically against the transmission gear by the expansion of said at least one elastic element, in particular to compensate for the relative elastic displacement between the disengagement wheel (under 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 The release wheel and the frame are arranged so that, in the event of an electrical failure of the clamping device, at least one elastic element is released in a direction capable of causing, in particular, the rotation of the release wheel and the transmission gear in order to induce the release stroke of the clamping device. Such a spiral arrangement of at least one elastic element makes it possible to impose an angular effect, more specifically, a rotational constraint on the release wheel.

[0015] The device for limiting the elastic extension of the disengagement wheel includes a stop element designed to define a disengagement position for a second release end of the partial gear teeth 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 prevent the other end of the partial gear teeth from engaging with the transmission gear during the elastic extension of the disengagement wheel. This limiting of the disengagement wheel's movement makes its operation more reliable under the various acceleration conditions (positive or negative) that a vehicle may encounter. Advantageously, according to the invention, the stop element can have different geometries and / or be mounted in different locations, such as, for example, 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 the release of said at least one flexible element in order to adapt to the stroke of the clamping stop, particularly during the replacement of 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 upon the first braking to the stroke 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 shown above arranged to bring the pair of friction elements closer to two opposite faces of the disc in order to clamp it.

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

[0019] Other features and advantages of the invention will become clear from the description given below, by way of example and not limitation, with reference to the accompanying drawings, in which:

[0020] [Fig-1] is a schematic top view of an example 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 example of a clamping device according to the invention;

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

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

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

[0026] [Fig. 9] and [Fig. 10] are partial front views of successive release stages of the clamping device and the example of the 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 cross-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 displacement 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 displacement 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 reference numerals, possibly with an additional subscript. Therefore, the description of their structure and function is not systematically repeated.

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

[0035] - an axial direction A, coinciding 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 disk 3; and

[0037] - a tangential direction T, perpendicular to the axial direction A, resulting from the friction by friction elements 2a, 2b approaching along the axial direction A pressing against the disc 3 rotating along an axis parallel to the axial direction A and fixed with a wheel 5 of a vehicle 4.

[0038] The invention applies to any type of braking system 1, in particular those intended for equipping passenger vehicles 4, SUVs ("Sport Utility Vehicles"), two-wheelers (in particular motorcycles), aircraft, industrial vehicles selected from vans, "Heavy Goods Vehicles" - i.e. subways, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or construction equipment - 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", we mean all types of braking systems 1 (four in [Fig.1]) comprising at least one electric actuator 12 intended to bring friction elements 2a, 2b closer together in order to laterally pinch a disc 3 attached to a wheel 5 of a vehicle 4 in order to brake it.

[0040] In the explanation below, reference is made to positive or negative rotation, in particular of the disengagement wheel 17. This does not mean that said rotations are necessarily respectively trigonometric and antitrigonometric, but simply that the rotations are in opposite directions, that is to say respectively a first direction of rotation for deactivation of the clamping device 7 (or release by the release mechanism 15) and the other second direction of rotation for activation of the clamping device 7 (or actuation of the release mechanism 15).

[0041] In the examples of Figures 2 and 3, a braking system 1 with a floating caliper-type clamping device 7 is used, thus limiting the number of electric actuators and resulting in a more compact design. The clamping device 7 consists of a frame 8 with an electric actuator 12 on one side and comprises 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 floating caliper-type clamping device 7 allows for the use of fewer electric actuators 12 and thus results in a more compact design. As is known per se, the clamping device 7 includes a control unit intended to manage each 12 electric actuator to provide the desired clamping force and all associated power and control elements in particular to manage the amplitude and force of bringing the friction elements 2a, 2b together.

[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, includes 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 closer together respectively in order to make contact with the disc 3.

[0043] The clamping device 7 is designed to exert a relative displacement between friction elements 2a, 2b by displacement along the axial direction A of a clamping stop 11. More specifically, the electric actuator 12 is connected at its output shaft 13 to a transmission gear 14 in order to allow the translational movement along the axial direction A of the clamping stop 11 and, incidentally, the movement of the friction elements 2a, 2b towards each other enabling braking or, conversely, the movement of the friction elements 2a, 2b away from each other enabling the release of braking.

[0044] Advantageously, according to the invention, the clamping device 7 includes a release mechanism 15 for the clamping stop 11, allowing, for example, in the event of a failure of the electric actuator 12, a release stroke of the clamping device 7 which is mechanically capable of automatically and reliably releasing any braking clamping exerted by the clamping stop 11. In the examples illustrated in Figures 3 to 16, the release mechanism 15 is coupled to the transmission gear 14 in a manner opposite to the mounting of the electric actuator 12. This arrangement is preferred to distribute the components substantially horizontally within the housing 15A of the frame 8.

[0045] Of course, a different configuration is possible to accommodate a different frame geometry without departing from the scope of the invention. The transmission gear 14 simply needs to be able to be driven by both the electric actuator 12 and the release mechanism 15 to remain within the scope of 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 rotatably mounted elastically on the frame 8 by means of the pivot shaft 17D about the axis of rotation B passing through the center of the pivot shaft 17D. Furthermore, the disengagement wheel 17 is provided with a partial peripheral toothing 17B intended to be coupled to the transmission gear 14 as, for example, illustrated in [Fig. 4]. As explained below, depending on the operation of the release mechanism 15, the disengagement wheel 17 may, temporarily or occasionally, become disengaged. 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 for rotational elastic mounting on the frame 8 by means of 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 teeth 17B as illustrated in the example in [Fig. 8]. It is therefore understood that the first actuating end EA is held elastically against the transmission gear 14 by the expansion 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 more clearly seen in the example of [Fig. 5], said at least one elastic element 15B is preferably wound around the axis B of rotation between the disengagement wheel 17 (one 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 inner level of the housing 15A of the frame 8) so as to, in the event of an electrical failure of the clamping device, generate a release 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 specifically, the retraction 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 that, particularly in the event of a failure of the electric actuator 12, a release stroke of the clamping device 7 by the drive of the transmission gear 14 is achieved solely through the elastic extension 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 14 to elastically move the disengagement wheel 17 (elastic contraction) when the clamping stop 11 is extended (braking activation) and returns this energy to the transmission gear 14 when the clamping stop 11 is retracted (braking deactivation). Ultimately, there is therefore no significant difference apart from the addition of the release mechanism 15. The clamping device 7 can thus maintain effective and consistent braking regardless of the wear of the friction elements 2a, 2b.

[0050] As seen in the examples in Figures 3 to 16, the disengagement wheel 17 includes a recess 17C (shaped like a disc arc in Figures 3 to 16) suitable for forming said partial peripheral teeth 17B. The recess 17C imposes a break in the partial peripheral teeth 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 whose one (or more) arm(s) 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 actuating end EA of the partial peripheral toothing 17B (maximum elastic contraction of the disengagement wheel 17 by the transmission gear 14) and a second releasing end EL of 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 at 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) at 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 operation according to the wear. Thus, the partial toothing also compensates for this wear of the friction elements 2a, 2b, as explained below.

[0053] Advantageously according to the invention, as seen in the example of figures 6 to 8, the partial peripheral toothing 17B is formed so as to drive, when the clamping device 7 is activated, the disengagement wheel 17, by the transmission gear 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] to 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.

[0054] According to an example illustrated in Figures 6 to 8, said predetermined maximum negative rotation may be between 160 degrees and 200 degrees, that is to say, 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 The clamping device 7, illustrated in [Fig. 6], moves from its resting position to its active position, illustrated in [Fig. 8]. It is therefore understood that the partial peripheral teeth 17B allow the absorption to be used only within a drive range determined by the transmission gear 14, that is, up to the first actuation end EA of the partial peripheral teeth 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 actuation end EA of the partial peripheral teeth 17B, causing a relative elastic displacement between the disengagement wheel 17 (under elastic contraction) and the transmission gear 14.It is therefore understood that the release mechanism 15 "recalibrates", advantageously according to the invention, to the stroke of the clamping stop 11 according to the wear of the friction elements 2a, 2b so that the rest angle of the disengagement wheel 17 repositions itself on the inactive position, such as the effective rest position of the clamping device 7 as illustrated in [Fig.6].

[0055] Therefore, particularly 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, regardless of the exit 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 release) to drive the assembly autonomously, i.e. in particular the transmission gear 14 and the deactivated electric actuator 12.Thus, when replacing the friction elements, the technician, unlike with current hydraulic systems, does not have to forcibly separate the two friction elements 2a and 2b. The friction elements 2a and 2b according to the invention will be automatically released, either partially or completely, from their inactive position, such as their rest position, depending on the wear that necessitated replacement. Finally, in the event of an electrical failure, generally related to an accident, the friction elements 2a and 2b according to the invention will be automatically released during braking to allow the vehicle to be moved.

[0056] Advantageously, according to the invention, the release mechanism 15 also includes a device 19 for limiting the elastic extension of the disengagement wheel 17 in order to improve the reliability of the release mechanism 15. Several embodiments are described below. However, in all embodiments, the limiting device 19 includes a stop element 19A for defining a disengagement position of the second end EL of the release of the partial peripheral teeth 17B, which, as will be explained in the embodiments of The details below may vary.

[0057] According to the invention, the disengagement position of the second end EL of the partial peripheral toothing release 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], i.e., 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 eliminate, the gap I (visible in [Fig. 10]) between the second release end EL of the partial peripheral gear 17B and the transmission gear 14. Furthermore, this prevents the actuating end EA of the partial peripheral gear 17B from engaging with the transmission gear 14 during the elastic release of the disengagement wheel 17 in the event of a potentially disproportionate elastic release of the disengagement wheel 17. The disengagement wheel 17 advantageously remains correctly indexed to the transmission gear 14. Thus, this limiting of the disengagement wheel 17's movement makes its operation more reliable under the various acceleration conditions (positive or negative) that a vehicle 4 may encounter.

[0059] Advantageously according to the invention, the stop element 19A can be of different geometries and / or implantation 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 preferably cooperates with at least one flexible element 19B so that the second end EL of the partial peripheral toothing 17B is held elastically against the transmission gear 14 by the release of said at least one flexible element 19B in order to adapt to the stroke of the clamping stop 11, particularly during the replacement of 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 17 with the transmission gear 14, and the release mechanism 15 is automatically recalibrated at the first braking to the stroke 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 on the inside of the housing 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 elastically eliminates the gap I (elastic compensation) between the second end EL of the partial peripheral toothing release 17B and the transmission gear 14. More precisely, the activation of the stop The clamping device 11 induces the position shown in [Fig. 7] or 8. If an electrical failure occurs (for example, the electric actuator 12 is no longer supplied with electrical energy), the release wheel 17 will elastically extend beyond the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig. 6] to reach the position shown in [Fig. 9], in which the stop element 19A comes into contact with the limiting element 17E. The release wheel 17 continues its movement by contracting at least one flexible element 19B until the release wheel 17 reaches its position illustrated in [Fig. 10]. At this moment, said at least one flexible element 19B by elastic release imposes a reverse rotation on the disengagement wheel 17 until the second end EL of release of the partial peripheral toothing 17B comes into contact with the transmission gear 14.Since the partial peripheral toothing 17B is held elastically meshed with the transmission gear 14, it is understood that the release mechanism 15 is automatically recalibrated at the first braking at the stroke of the clamping stop 11 as explained above.

[0062] According to a second embodiment illustrated in [Fig. 12] and 13, the stop element 19A is fixedly mounted on the disengagement wheel 17. The stop element 19A cooperates with at least one flexible element 19B mounted internally on the housing 15A of the frame 8. In this second embodiment, the limiting device 19 makes it possible to elastically cancel the gap I (elastic compensation) between the second end EL of the release of the partial peripheral teeth 17B and the transmission gear 14. More specifically, whether the activation of the clamping stop 11 induces the position of the example in [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 go beyond the inactive position, such as the rest position, of the clamping device 7 illustrated in [Fig.6] to reach that of [Fig.[9] in which the stop 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 release, imposes a reverse rotation on the disengagement wheel 17 until the second release end EL of the partial peripheral teeth 17B comes into contact with the transmission gear 14 as illustrated in [Fig. 13]. The partial peripheral teeth 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 of the stroke of the clamping stop 11 as explained above.

[0063] According to a third embodiment illustrated in Figures 14 to 16, element 19A The stop is fixedly mounted on the inside of the housing 15A of the frame 8. The stop element 19A essentially comprises a fixed part 19A1 mounted on the inside of the housing 15A of the frame 8 and a rocker part 19A2 pivotally mounted on the fixed part 19A1 at the axis O. In this third embodiment, the limiting device 19 allows the gap I (elastic compensation) between the second end EL of the release of the partial peripheral teeth 17B and the transmission gear 14 to be limited. More specifically, whether the activation of the clamping stop 11 induces the position of the example in [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 go beyond 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 it reaches the position shown in [Fig. 16]. At this point, the disengagement wheel 17 contacts the rocker-shaped part 19A2 and stops in a position where the second end EL of the partial peripheral toothing 17B is no longer in contact with the transmission gear 14, as shown in [Fig. 16], but is reasonably close. To make the release mechanism 15 functional again, the disengagement wheel 17 must be re-engaged. The release mechanism 15 is then automatically recalibrated during the first braking action at the stroke of the clamping stop 11, as explained above. As shown in [Fig. 15], in the direction of rotation during braking, the disengagement wheel 17 is not prevented from passing the stop element 19A by pivoting of the rocker-shaped part 19A2. .

[0064] In order to limit the risk of the rocker part 19A2 jamming against the disengagement wheel 17, the limiting device 19 preferably comprises a pivoting roller 19A3 mounted at the end of the rocker 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 shown, and other embodiments and variants will be obvious 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 no limitation, it is possible to combine a stop 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 - building 9 - screed 10 - stirrup 11 - clamping stop 12 - electric actuator 13 - output tree 14 - transmission gear 15 - release mechanism 15A - casing 15B - elastic element 17 - Disengagement wheel 17 A - plate 17B - partial peripheral dentition 17C - obviously 17D - pivot shaft 17E - limiting element 19 - device for limiting the elastic extension of the disengagement wheel 19A - stop element 19A1 - fixed part of the stop element 19A2 - part forming the rocker of the stop element 19A3 - swiveling roller of the stop element 19B - flexible element A - axial direction B - axis of rotation of the disengagement wheel I - gap between the second end of the partial peripheral toothing release and the transmission gear O - axis of rotation of the stop element R - radial direction T - tangential direction EA - first actuation end of the partial gearing EL - second end of partial denture release

Claims

Demands

1. A 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) for providing a clamping force to a clamping stop (11) by means of a transmission gear (14) in order to allow the relative displacement 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) rotatably mounted elastically on the frame (8) and having 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) through the elastic release of the wheel (17) disengagement,and in that the release mechanism (15) includes a device (19) for limiting the elastic extension of the disengagement wheel (17) in order to improve the reliability of the operation of the release mechanism (15).

2. Clamping device (7) according to the preceding claim, in which the disengagement wheel (17) has a recess (17C) suitable for forming said partial peripheral teeth (17B) so as to drive, when the clamping device (7) is activated, the release wheel (17), by the transmission gear (14), through a maximum negative rotation of between 160 degrees and 200 degrees between an inactive position of the clamping device (7) and an active position of the clamping device (7) in order to adapt to the stroke of the clamping stop (11) according to the wear of the friction elements (2a, 2b).

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

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

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9.

10.

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 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, wherein the device (19) for limiting the elastic release of the disengagement wheel (17) comprises a stop element (19A) intended to define a disengagement position of one end (EL) of the release of 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 prevent the other end of the partial toothing (17B) from engaging with the transmission gear (14) during the elastic release of the disengagement wheel (17). Clamping device (7) according to the preceding claim, wherein 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 detent of said at least one flexible element (19B) in order to adapt to the stroke 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 bracket type. Vehicle braking system (1) 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) closer to 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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