Device for the recovery of end forces of segments for drum brake, drum brake equipped with such a device for the recovery of end forces of segments and method of implementing such a device for the recovery of end forces of segments.

Abstract

The invention relates in particular to a drum brake for road vehicles, especially automobiles, said drum brake comprising a first and a second segment (1, 2) having stop ends (11, 21) bearing on an anchoring element connected to the backing plate, which includes a force-response device (4). The latter comprises two stops (41, 42), positioned on either side of said device between a rest position, where they are separated from each other by the action of at least one elastically deformable element (61, 62) bearing on the anchoring element, and an active position, in which they come into contact with each other. The elastically deformable element has a setting adapted to a predetermined braking force, to cause the stops to move from their rest position to their active position, thus enabling the transition from a first simplex braking function to a second dual-servo braking function.Figure for the abbreviation: [Fig.1].

Description

Title of the invention: Device for the recovery of end forces of segments for drum brake, drum brake equipped with such a device for the recovery of end forces of segments and method of implementing such a device for the recovery of end forces of segments. FIELD OF INVENTION

[0001] The invention relates to a drum brake for a road vehicle, in particular for a light or heavy motor vehicle. STATE OF THE ART

[0002] In a motor vehicle, the service brake function is primarily to slow the vehicle down and bring it to a stop. In most current automobiles, the service brake is provided by drum brakes or disc brakes, or discs at the front of the vehicle and drums at the rear.

[0003] The invention relates to a device implemented in a drum brake.

[0004] A drum brake can have several modes of operation: a so-called "simplex" operation and a "duo-servo" operation.

[0005] In "simplex" mode, an actuator separates two movable ends of the segments, while their opposite ends (stop ends) both come to rest against an anchoring element.

[0006] In "duo-servo" mode, the actuator also separates the two moving ends of the segments but, in addition, the ends of the segments opposite the moving ends are pressed against each other so that the movement of one of the two segments is transmitted to the other segment, to increase the braking force.

[0007] In simplex mode, the braking force is therefore less than in duo-servo mode, but has the advantage of being easier to control, particularly by the trajectory control system. Simplex mode offers the advantage of allowing more precise modulation.

[0008] One object of the invention is to overcome, in whole or in part, the disadvantages of the prior art.

[0009] In particular, one aim is to produce a drum brake which allows for better efficiency, or which can be controlled more precisely, or a better compromise between the two. Description of the invention

[0010] The invention relates to a new device to replace the second actuator device. The new device according to the invention is designed to provide either a so-called "simplex" operating mode or a so-called "duo-servo" operating mode.

[0011] The invention also relates to a drum brake and vehicle or a vehicle sub-assembly incorporating a drum brake equipped with such a device, as well as a brake control method implementing such a device.

[0012] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a drum brake for a road vehicle, in particular a motor vehicle, said drum brake comprising:

[0013] - a first and a second segment supported by a plate, capable of causing a friction braking, said segments having movable ends opposite each other and stop ends, opposite said movable ends, bearing on an anchoring element linked to the plate (or fixed point), - an actuator which, in response to a braking force requested, causes the two movable ends of said segments to move apart, thus ensuring a first braking function in a first simplex operating mode which brings the brake into a first braking position.

[0014] In accordance with the invention, said drum brake is notable: in that the anchoring element comprises a device for absorbing end loads from segments, positioned between the two ends of the abutment, and in that the device for absorbing end forces of segments comprises two stops, positioned on either side of said device, facing the end stops of the segments, each capable of coming into contact with an end stop, the two stops being movable in displacement between: - a rest position, in which the two stops are separated from each other, under the action of at least one elastically deformable element that bears against the anchoring element, and - an active position, according to which the two stops come into contact with each other, said elastically deformable element having a setting adapted to a predetermined braking force, beyond which the elastically deformable element deforms sufficiently, under the action of a push on one of said stops caused by a stop end of segment in the first braking position to cause the stops to pass from their rest position to their active position, the active position allowing a resumption of forces from one segment to the other by contact of the stops with each other and with the stops ends of the segments, said resumption of forces allowing the passage from the first braking function to a second braking function in a second operating mode of the duo-servo type.

[0015] In particular, the anchoring element on which the elastically deformable element rests is that of the segment which is compressed during forward braking.

[0016] Advantageously, the elastically deformable element is prestressed in the rest position of the stops.

[0017] Preferably, the elastically deformable and prestressed element is enclosed in a cage.

[0018] Preferably, the force recovery device comprises two elastically deformable and possibly prestressed elements, each stop being associated with an elastically deformable element possibly prestressed which maintains it in the resting position when no braking action is engaged.

[0019] According to an alternative embodiment, the stops are aligned in at least one housing which includes said at least one elastically deformable and possibly prestressed element.

[0020] Preferably, the force recovery device includes at least one position sensor for at least one stop, to determine the stop's displacement information, in particular from said rest position to said active position or even between the two, as well as a module for receiving and transmitting said displacement information to an external control unit. The stop associated with the position sensor is preferably the one that receives the segment that is compressed during forward braking.

[0021] According to a particular embodiment, said position sensor is a hall effect stroke sensor.

[0022] According to yet another advantageous embodiment, the force recovery device comprises two position sensors, each of the sensors being associated with a stop, making it possible to determine a displacement information for each of the stops, in particular between their rest position and their active position or even between the two.

[0023] In addition, the brake according to the invention includes a protective cover for said at least one position sensor and said receiving and transmitting module, said cover being optionally removable.

[0024] According to a second aspect of the invention, it also relates to a hydraulic braking system which includes at least one drum brake as defined above.

[0025] According to a third aspect of the invention, it also relates to an electromechanical braking system, in particular without hydraulics, which includes at least one drum brake as defined above.

[0026] According to a fourth aspect of the invention, it also relates to a method for adapting a braking system as defined above, comprising a brake with drum also as defined above, equipped with a force recovery device which includes two stops moving between: - a rest position, in which the two stops are separated from each other, under the action of at least one elastically deformable element linked to the anchoring element and - an active position, in which the two stops come into contact with each other, said elastically deformable element having a calibration adapted to a predetermined braking force, said adaptation process comprising the following steps: - determination of a predetermined braking force to be applied for the drum brake to operate according to said second duo-servo operating mode, and - calibration of the elastically deformable element according to said predetermined braking force.

[0027] According to a fifth aspect of the invention, it relates to a method for controlling a brake system as defined above, comprising a drum brake also as defined above and a pilot unit.

[0028] The control method is remarkable in that, characterized in that said control unit performs the following steps: - receiving a braking instruction, in particular by a driver pressing the brake pedal, - determination of a target braking force, - receipt of at least one displacement information from at least one stop of said force transfer device from the drum brake reception and transmission module, - determines the actual braking force based on the received displacement information, - comparison of said actual braking force to said setpoint braking force and, - if the actual braking force is less than the said setpoint braking force, then the actual braking force is increased until the actual braking force is at least equal to the said setpoint braking force.

[0029] Otherwise, if the actual braking force is greater than the setpoint braking force, then the braking force is reduced: the method here aims to regulate, in a closed loop, the value of the braking force, to obtain a braking force corresponding to the setpoint braking force.

[0030] The invention also relates to a road vehicle, in particular a motor vehicle, comprising a braking system as defined above.

[0031] Finally, the invention relates to a device for absorbing end-segment forces, which comprises: - a first stop comprising a head for absorbing forces from the ends of segments of a drum brake, a contact face axially opposite to said head and arranged between said head and said contact face means for absorbing forces from a first end of a first spring, typically a shoulder; - a second stop comprising a head for absorbing forces from the ends of segments of a drum brake, a contact face axially opposite to said head and arranged between said head and said contact face means for absorbing forces from a first end of a second spring, typically a shoulder; - the aforementioned first and second jurisdictions; - a casing equipped with means for securing it to a drum brake plate, means for receiving and guiding the first stop equipped with the first spring, means for receiving and guiding the second stop equipped with the second spring, the first and second stops being arranged head-to-tail and means for taking up forces from the second ends of the springs.

[0032] Advantageously, the force recovery device includes means for pre-stressing the springs and the receiving and guiding means ensure translational guidance of the first and second stops between a first position in which said first and second stops are not in mutual contact and a second position in which the contact faces of the first and second stops are in mutual contact.

[0033] LIST OF FIGURES

[0034] Other features and advantages of the invention will become apparent from the detailed description of implementations and embodiments, which are by no means limiting, and from the accompanying drawings where:

[0035] [Fig. 1] is a top view of a part of a drum brake according to the invention,

[0036] [Fig.2] is a perspective view of a force recovery device housing according to the invention,

[0037] [Fig.3] is a schematic and cross-sectional representation of a brake force recovery device according to the invention,

[0038] [Fig.4] illustrates stops and elastically deformable elements comprising the device of [Fig.3], the stops being in the rest position,

[0039] [Fig.5] illustrates stops and elastically deformable elements comprising the device of [Fig.3] or [Fig.4], the stops being in the active position,

[0040] [Fig. 6] partially illustrates the force recovery device according to the invention, seen in perspective, comprising a position sensor for a stop, and means techniques for retrieving and transmitting information about the position of the stop to a remote control unit,

[0041] [Fig.7] is a perspective view of a brake force recovery device according to the invention, illustrating an embodiment in which the device comprises two stops and two position sensors,

[0042] [Fig.8] partially represents and is shown in perspective view of a drum brake and the force-recovery device equipped with a protective cover, the cover being partially shown in section, and

[0043] [Fig.9] is a schematic representation of a method according to the invention.

[0044] DESCRIPTION OF EMBODIMENT METHODS

[0045] The embodiments that will now be described are not limiting: in particular, variants of the invention may be made comprising only a selection of features described below, isolated from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0046] Of course, the invention is not limited to the examples that will be described, and many modifications can be made to these examples without departing from the scope of the invention. Furthermore, the various features, forms, variants, and embodiments of the invention can be combined with one another in various ways, provided that they are not incompatible or mutually exclusive.

[0047] The invention applies mainly to drum brakes, intended to equip vehicles, particularly motor vehicles (but not exclusively).

[0048] In a conventional manner, the drum brake comprises two segments 1 and 2 arranged inside a cylinder 3.

[0049] Fig. 1 shows part of cylinder 3 and part of segments 1 and 2.

[0050] The two segments carry brake linings 10 and 20, respectively, which come to rub against the cylinder when the segments are pressed against the inner surface of the cylinder 3.

[0051] To induce braking, the segments are moved away from their rest position: each of them thus has, for this purpose, a first movable end (not illustrated in the figures).

[0052] The moving ends of the segments are opposite each other and are driven into movement by an actuator device which, in response to an applied braking force, controls the separation of the two moving ends of said segments from each other, thus ensuring a first braking function in a first simplex operating mode which brings the brake into a first braking position.

[0053] The other ends of segments 1 and 2 are called stop ends 11 and 21: they are opposite the movable ends and are illustrated in figures 1 and 3 to 6.

[0054] According to the invention, the drum brake includes a force recovery device, which is positioned between the two ends of the stop 11 and 21.

[0055] The force recovery device has the function of transmitting a force from one end of the stop to another, so that segment 1 transmits a movement to segment 2.

[0056] To do this, the force recovery device 4 comprises the following elements:

[0057] It includes two movable elements forming stops 41 and 42, which are positioned opposite the stop ends 11 and 21 of segments 1 and 2, respectively.

[0058] The stops are received in a housing 5, of substantially cylindrical shape and open at both ends: the housing 5 thus forms a sleeve, placed between the two stops of segments 1 and 2.

[0059] Figures 3 to 5 show how the movable elements 41 and 42 are positioned and how they are made.

[0060] Each stop comprises a rod 40, the axis of which is positioned in the axis of the housing 5, and each rod has, at its end, a flat head 30 against which the stop ends 41 and 42 of segments 1 and 2 can come to rest.

[0061] It is noted on [Fig.3] that the free ends forming contact faces 34 (of the stop rods 41 and 42) do not touch in the rest position of the force recovery device 4.

[0062] In the context of the example presented, the housing 5 of the transmission device 4 comprises two cylindrical chambers 51 and 52, coaxial and adjacent, forming receiving and guiding means: chamber 51 receives the stop 41 and chamber 52 receives the stop 42.

[0063] In figures 2 and 4, it can be seen that an internal radial annular wall 53 separates the two sub-chambers 51 and 52 and forms a means of force retrieval, a communication opening being present between the two sub-chambers, to allow the contact face 34 of the rod 40 of the element 41, to pass through the wall 53, to come into contact with the contact face 34 of the rod 40 of the stop 42 ([Fig.5]).

[0064] The transmission device also includes two springs 61 and 62, each positioned in a sub-chamber 51 and 52 around the stems of the stops 41 and 42.

[0065] The two springs bear against the rear face of a flat head 30 of a stop and against the internal radial annular wall 53 of the housing 5.

[0066] By moving, under the action of the thrust of the end of the stop 11 or 21 of the segments 1 and 2 on the heads 30 of the stops 41 and 42, the stops compress the springs 61 and 62 until their contact faces 34 come into contact.

[0067] In the example described, the transmission device comprises two springs 61 and 62. However, it should be understood that the brake force recovery device according to the invention could comprise only one elastically deformable element, or different elastically deformable elements (such as Belleville washers, for example), without departing from the scope of the invention.

[0068] Thus implemented, the brake force absorption device according to the invention comprises two stops 41 and 42, positioned on either side of said device 4, which face the stop ends 11 and 21 of segments 1 and 2. The stop ends 11 and 21 are adapted to each come into contact with a stop of the force absorption device 4, the two stops 41 and 42 being movable in displacement between: - a rest position (see [Fig.3]), in which the two stops 41 and 42 are separated from each other, under the action of at least one elastically deformable element (in the example, these are the springs 61 and 62), and - an active position, according to which the two stops come into contact with each other (see [Fig.5]).

[0069] In accordance with the invention, the springs each have a setting adapted to a predetermined braking force, beyond which they deform under the action of a push from one of said stops 41 and 42 caused by an end of stop 11 and 21 of segment 1 and 2 in the first braking position.

[0070] The deformation of the springs ensuring the passage of the stops from their rest position to their active position.

[0071] In other words, depending on the setting of the spring(s), the thrust exerted by the end of the stop 11 or 21 on the stop 41 or 42 is not strong enough to overcome the resistance of the spring 61 or 62: in this case, the brake operates in simplex mode.

[0072] But if the thrust exerted by the end of the stop 11 or 21 on the stop 41 or 42 is strong enough to overcome the resistance of the spring 61 or 62, and compress them, then the contact faces 34 of the stops 41 and 42 touch and the brake changes from its simplex operating mode to duo-servo mode: in this case, one of the segments 1 and 2 pushes the other segment which moves further apart and increases the braking.

[0073] The active position of the stops 41 and 42 of the force recovery device 4 thus ensures a transmission of movement from one segment to another by contact of the stops 41 and 42 with the ends of the stops 11 and 21 of the segments, said transmission of movement allowing the transition from the first braking function to a second braking function in a second duo-servo operating mode.

[0074] The calibration of the spring(s) thus determines the transition from simplex mode to duo-servo mode.

[0075] In other words, the spring rate is adapted to a predetermined braking force, beyond which the elastically deformable element (the or the springs) deforms sufficiently, under the action of a push from one of said stops caused by a stop end of segment in the first braking position, to cause the stops to pass from their rest position to their active position, the active position allowing a resumption of forces from one segment to another by contact of the stops with each other and with the stops ends of the segments, said resumption of forces allowing the passage from the first braking function to a second braking function in a second operating mode of the duo-servo type.

[0076] By way of example, for drum brakes with the following dimensions, the spring resistance was determined to switch from simplex mode to duo-servo mode:

[0077] a) for a drum brake with a diameter of 9 inches (22.86 cm), the spring has a resistance of at least 9000 N to switch from simplex mode to duo-servo mode,

[0078] b) for a drum brake with a diameter of 10 inches (25.4 cm), the spring has a resistance of at least 10,000 N to switch from simplex mode to duo-servo mode, and

[0079] c) for a drum brake with a diameter of 11 inches (27.94 cm), the spring has a resistance of at least 12,500 N to switch from simplex mode to duo-servo mode.

[0080] In simplex mode, if we consider a brake as illustrated in [Fig.1], the left segment 1 is in compressed mode and the right segment is in tensioned mode.

[0081] If heavy braking is required, a change in braking mode is also required, switching from simplex mode to duo-servo mode. In the latter case, the left segment 1 (in the figures) is compressed, and the right segment (segment 2) also becomes a compressed segment.

[0082] During the design of the brake, and in particular the force-recovery device, a braking force to be applied for the drum brake to operate according to said second duo-servo operating mode is predetermined. The calibration of the deformable elastic element is established as a function of said predetermined braking force.

[0083] To facilitate assembly, in particular, it is provided that the springs 61 and 62 are pre-stressed in the rest position of the stops 41 and 42. For example, the springs 61 and 62 can be pre-stressed by enclosing them in cages 71 and 72, respectively, as can be seen in [Fig.4].

[0084] The cages also facilitate the positioning of the springs during assembly.

[0085] Indeed, during the assembly of the force recovery device, the cages 71 and 72 comprising the pre-stressed springs are inserted into the sub-chambers 51 and 52, then the stops 41 and 42 are positioned.

[0086] Reference will now be made to figures 6 to 8.

[0087] In the illustrated embodiment, it is planned to equip the force recovery device 4 comprising two position sensors 43 and 44, each precisely determining the position of a stop (respectively 41 and 42), in order to determine a displacement information II (respectively 12) of the stop (respectively 41 and 42), for example between the rest position of the stop concerned and its active position.

[0088] In this embodiment, the position sensors 43 and 44 are Hall effect stroke sensors. It should be understood that the invention is not limited to the choice of this type of sensor and extends to the implementation of any equivalent means.

[0089] This displacement information is taken into consideration in a control law, for example, of the brake, to increase its operating accuracy.

[0090] To do this, the force recovery device is also equipped (or associated with) a module 45 for receiving this displacement information detected by the sensor, the module 45 also ensuring the transmission of this displacement information to an external control unit.

[0091] To achieve this, as illustrated in [Fig. 6] for example, the module 45 is carried by an electronic circuit 46 fixed to the outer wall of the housing 5 of the force-recovery device. It is connected by cables 47 to a connector 48 fixed to the brake plate, the connector 48 itself being connected to the appropriate electronic system external to the brake.

[0092] In order to protect the whole from dust, in particular it is planned to enclose the circuit 46 equipped with the receiving module 45 and the sensors 43 and 44 under a protective cover 50 which may, possibly, be removable.

[0093] Reference will now be made to [Fig.9], which schematically illustrates a control method for a drum brake system that has just been presented.

[0094] The braking system is schematically represented by reference 6. It may be a hydraulic braking system 6, or an electromechanical braking system 6, in particular without hydraulics.

[0095] Each of the brake systems 6 includes at least one drum brake as described in Figures 1 to 8.

[0096] The control unit is schematically illustrated by reference 7.

[0097] The control unit 7 performs the following steps:

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[0110] [YES]

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[0124] It receives a braking command C, for example when a driver activates the vehicle's brake pedal. The control unit 7 then determines a setpoint braking force F(C). In parallel, the control unit 7 receives information II and 12 which concern the respective movements of the stops 41 and 42 of the force recovery device, from the receiving and transmission module 45 of the drum brake. The control unit 7 determines, from the information II and 12, the actual braking force FR, and compares this actual braking force FR to the said setpoint braking force F(C). If the actual braking force FR is less than the said setpoint braking force F(C), then the actual braking force FR until the actual braking force is at least equal to the said setpoint braking force. Conversely, if the actual braking force FR is greater than the said setpoint braking force F(C), then the actual braking force is decreased until the actual braking force is equal to the setpoint braking force. From the preceding description, we understand how the invention achieves its objectives. It should be understood that the invention is not limited to the examples of implementation presented above, and that it extends to the implementation of any equivalent means. NOMENCLATURE 1: first segment 2: second segment 3: cylinder 4: Device for transferring end-segment forces 5: crankcase 6: Drum brake system 7: piloting unit 10: garnish 11: end of stop 20: garnish 21: end of stop 30: flat head of stops 41 and 42 34: contact face 40: stem of each of the stops 41: stop 42: stop 43: Position sensor 44: Position sensor

[0125] 45 receiving and transmission module

[0126] 46 electronic circuit

[0127] 47 connecting cables

[0128] 48 connector

[0129] 50 protective cover

[0130] 51 receiving and guiding means (sub-chamber)

[0131] 52 receiving and guiding means (sub-chamber)

[0132] 53 force absorption means (internal wall separating the sub-chambers)

[0133] 61 first spring

[0134] 62 second spring

[0135] 71 cage

[0136] 72 cage

[0137] II: information concerning the displacement of element 41

[0138] II: information concerning the displacement of element 42

[0139] FR: actual braking force

[0140] F(C): setpoint force

[0141] C: instruction

Claims

1. Demands Drum brake for road vehicles, particularly automobiles, said drum brake comprising: - a first and a second segment (1,2) carried by a plate, capable of causing braking by friction, said segments (1,2) having movable ends opposite each other and stop ends (11, 21), opposite said movable ends, bearing on an anchoring element attached to the plate, - an actuator which, in response to a braking force requested, causes the two movable ends of said segments (1,2) to separate from each other, thus ensuring a first braking function in a first simplex operating mode which brings the brake into a first braking position, said drum brake being characterized in that the anchoring element includes a force-recovery device (4), positioned between the two stop ends (11,21), and in that the force-response device comprises two stops (41, 42), positioned on either side of said device, facing the stop ends (11, 21) of the segments (1, 2), each capable of coming into contact with a stop end (11, 21), the two stops (41, 42) being movable in displacement between: - a rest position, according to which the two stops (41, 42) are separated from each other, under the action of at least one elastically deformable element (61, 62) which bears against the anchoring element, and - an active position, in which the two stops (41, 42) come into contact with each other, said at least one elastically deformable element (61, 62) having a setting adapted to a predetermined braking force, beyond which said at least one elastically deformable element (61, 62) deforms sufficiently under the action of a thrust on one of said stops (41, 42) caused by a stop end of segment (11, 21) in the first braking position to cause the stops (41, 42) to move from their rest position to their active position, the active position allowing a transfer of forces from one segment to the other by contact of the stops (41, 42) with each other and with the stop ends of the segments (11,21), said resumption of effort allowing the transition from the first braking function to a second braking function in a second operating mode of the duo-servo type.

2. Drum brake according to claim 1, characterized in that said at least one elastically deformable element (61, 62) is pre-stressed in the rest position of the stops (41, 42).

3. Drum brake according to claim 2, characterized in that said at least one elastically deformable and prestressed element (61, 62) is enclosed in a cage.

4. Drum brake according to any one of the preceding claims, characterized in that said force recovery device (4) comprises two elastically deformable elements (61, 62) and optionally prestressed, each of said stop (41, 42) being associated with an elastically deformable element (61, 62) optionally prestressed which maintains it in the open rest position when no braking action is engaged.

5. Drum brake according to any one of the preceding claims, characterized in that said stops (41, 42) are aligned in at least one housing (5) which includes said at least one elastically deformable element (61, 62) and optionally prestressed.

6. Drum brake according to any one of the preceding claims, characterized in that the force recovery device (4) comprises at least one position sensor (43, 44) of at least one stop (41, 42), for determining at least one displacement information (II, 12) of said at least one stop (41, 42), in particular from said rest position to said active position or even between the two, as well as a module (45) for receiving and transmitting said at least one displacement information (II, 12) to an external control unit (7).

7. Drum brake according to claim 6, characterized in that said at least one position sensor (43, 44) is a hall effect stroke sensor.

8. Drum brake according to any one of claims 6 or 7, characterized in that said force-recovery device (4) comprises two position sensors (43, 44), each of the position sensors being associated with a stop (41, 42), making it possible to determine a displacement information (II, 12) for each of the stops (41, 42), in particular between their resting position and their active position, or even between the two.

9. Drum brake according to claim 6, 7 or 8, characterized in that it comprises a protective cover (50) of said at least one position sensor (43, 44) and of said receiving and transmitting module (45), said cover (50) being optionally removable.

10. Hydraulic braking system (6), characterized in that it comprises at least one drum brake according to any one of the preceding claims.

11. Electromechanical braking system (6), in particular without hydraulics, characterized in that it comprises at least one drum brake according to any one of claims 1 to 9.

12. A method for designing a braking system (6) according to any one of claims 10 or 11, comprising a drum brake according to any one of claims 1 to 9, equipped with a force-response device (4), comprising two movable elements (41, 42) moving between: - a rest position, according to which the two stops (41, 42) are separated from each other, under the action of at least one elastically deformable element (61, 62) connected to the anchoring element, and - an active position, according to which the two stops (41, 42) come into contact with each other, said at least one elastically deformable element (61, 62) having a setting adapted to a predetermined braking force (F(C)), said design method comprising the following steps: - determining a predetermined braking force (F(C)) to be applied so that the drum brake operates according to the aforementioned second dual-servo operating mode,and - calibration of said at least one elastically deformable element (61, 62) as a function of said predetermined braking force (F(C)).

13. A method for controlling a brake system (6) according to claim 10 or 11, comprising a drum brake according to any one of claims 6 to 9 and a control unit (7), characterized in that said control unit (7) performs the following steps: - receiving a braking command (C), in particular by actuation of a brake pedal by a driver,

14.

15. - determination of a setpoint braking force (F(C)), - reception of at least one displacement information (II, 12) from at least one stop (41, 42) of said force recovery arrangement (4) from the drum brake receiving and transmission module (45), - determines an actual braking force (FR) as a function of said at least one displacement information (II, 12) received, - comparison of said actual braking force (FR) to said setpoint braking force (F(C)) and, - if the actual braking force (FR) is less than the said setpoint braking force (F(C)), then the actual braking force (FR) is increased until the actual braking force (FR) is at least equal to the said setpoint braking force (F(C)), or if the actual braking force (FR) is greater than the said setpoint braking force (F(C)), then the actual braking force (FR) is decreased until the actual braking force (FR) is equal to the setpoint braking force (F(C)). Road vehicle, in particular motor vehicle, comprising a braking system (6) according to claim 10 or 11. Device for absorbing end loads from segments, for the anchoring element of a drum brake according to any one of claims 1 to 9, characterized in that: - said first stop (41) includes a head (30) for receiving forces from the ends of segments of said drum brake, a contact face (34) axially opposite said head (30) and, arranged between said head (30) and said contact face (34), means for receiving forces from a first end of a first spring (61), typically a shoulder; - said second stop (42) includes a head (30) for receiving forces from the ends of segments of said drum brake, a contact face (34) axially opposite said head (30) and, arranged between said head (30) and said contact face (34), means for receiving forces from a first end of a second spring (62), typically a shoulder; - said first and second springs (61, 62), each forming one of said elastically deformable elements (61, 62) having a setting adapted to a predetermined braking force, - a casing (5) equipped with means for securing it to the drum brake plate, means for receiving and guiding (51, 52) the first stop (41) equipped with the first spring (61), means for receiving and guiding the second stop (42) equipped with the second spring (62), the first and second stops (41, 42) being arranged head-to-tail and means (53) for taking up forces from the second ends of the springs (61, 62).

16. Force recovery device according to claim 15, characterized in that it comprises means for pre-stressing the springs (61, 62), and in that the receiving and guiding means (51, 52) ensure translational guidance of the first and second stops (41, 42) between a first position in which said first and second stops (41, 42) are not in mutual contact and a second position in which the contact faces (34) of the first and second stops (41, 42) are in mutual contact.

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