SIMPLEX DRUM BRAKE AND DUO SERVO INCLUDING A CAM DRIVE SYSTEM

Abstract

The invention relates to a drum brake (2) for a motorized road vehicle wheel. The drum brake (2) is configured to brake the wheel in simplex mode during service braking and in duo servo mode during parking braking of the vehicle. The brake (2) comprises a plate (20) and a braking lever (9) which is configured to pivot relative to the plate (20) during parking braking of the vehicle (1). The brake (2) comprises a cam drive system (6), which comprises a cam (8), for parking braking of the wheel. The lever (9) is configured to pivot by driving the cam (8), the cam (8) urging the first segment (21) or the second segment (23) against the drum (3), during parking braking of the vehicle. (Fig. 3)

Description

Title of the invention: SIMPLEX DRUM BRAKE AND DUO SERVO COMPRISING A DRIVE SYSTEM CAM Technical field of the invention

[0001] The invention relates to the braking of a motor vehicle. It relates to a drum brake for a road vehicle, such as an automobile. The drum brake is in particular configured to brake in simplex mode for service braking and in duo servo mode for parking braking. State of the prior art

[0002] [Fig. 1] shows a drum brake 2 for a motorized road vehicle 1 which is known from the state of the art. The brake 2 comprises a drum 3, a plate 20, a first segment 21, a second segment 23, a first actuator 5, a fixed point 4, a braking lever 9 and a reaction rod 24. The reaction rod 24 is connected to the braking lever 9 and to the second segment 23.

[0003] The drum brake 2 operates in simplex mode during service braking. During service braking, the first actuator 5 forces the first segment 21 and the second segment 23 apart from each other, each of which forces them against the drum 3. During parking braking, the lever 9 pivots, forcing the first segment 21 against the drum. By pivoting, the lever 9 forces the second segment 23 against the drum via the reaction rod 24.

[0004] Parking braking is likely to be particularly intense, particularly in view of commercial or regulatory requirements. When parking braking is motorized, each electromechanical actuator of the brake is mechanically and fluidically protected, for example against shocks and against humidity.

[0005] The drum brake 2 has a significant bulk in the vicinity of the first actuator 5. The bulk in the vicinity of the first actuator 5 complicates the manufacture of the brake and the installation of the brake 2 on a motorized road vehicle hub.

[0006] There is a need for a motor vehicle brake that provides stable and precise braking during service braking and intense braking during parking braking, while being easier to manufacture and install and while limiting the mass and size of the motor vehicle brake. Statement of the invention

[0007] The invention aims to remedy all or part of the drawbacks of the state of the art mentioned above.

[0008] In this regard, the invention relates to a drum brake module for a wheel of motorized road vehicle. The brake module comprises a plate, a first braking segment and a second braking segment which are connected to the plate while being rotatable relative to the plate, a first actuator and a braking lever. The first actuator is configured to urge the first braking segment and the second braking segment apart towards a drum to brake the wheel during service braking of the vehicle. The braking lever is configured to pivot relative to the plate during parking braking of the vehicle.

[0009] The drum brake is configured to brake the wheel in dual servo mode during parking braking. During braking in dual servo mode, the first braking segment and the second braking segment move in particular in rotation in the same direction relative to the plate, an intermediate element of the brake module transmitting in particular a force from one of the segments to the other of the segments.

[0010] According to the invention, the brake module comprises a cam drive system for parking braking the wheel. The cam drive system comprises a cam. During parking braking of the vehicle, the brake lever is configured to pivot by driving the cam, the cam urging the first segment or the second segment against the drum.

[0011] Thanks to the brake module as claimed, the service braking is stable and precise and the parking braking is particularly intense, while having a brake that is easy to manufacture and install and while limiting the mass and size of the motor vehicle brake. The drum brake is configured to brake the wheel in simplex mode by spreading the segments during service braking, which allows stable and precise braking of the wheel. The drum brake is configured to brake the wheel in duo servo mode during parking braking, which allows particularly intense braking of the wheel.

[0012] Since parking braking is likely to be particularly intense, the mass and size of the drum brake can be reduced compared to the mass and size of the drum brake of known structure.

[0013] The manufacture of the drum brake and the installation of the drum brake tend to be facilitated compared to the manufacture and installation of the drum brake of known structure, in particular due to a limited size of the brake near the first actuator and the hub.

[0014] When the parking brake is motorized, an electromechanical actuator can be arranged near the first actuator for service braking, effectively protecting the actuators mechanically and fluidically, for example against shocks and humidity.

[0015] According to a particular embodiment, the cam comprises at least a first drive portion. The first drive portion is configured to mechanically engage the lever by tending to rotate the cam relative to the platter as the lever pivots relative to the platter.

[0016] According to a particular embodiment, the cam comprises a first tooth configured to mechanically drive the first segment. The first tooth is configured to mechanically drive the first segment by urging the first segment against the drum.

[0017] According to a particular embodiment, the cam comprises an oblong orifice for the passage of a central shaft of the cam drive system.

[0018] According to a particular embodiment, the central shaft is configured to slide inside the oblong orifice relative to the cam. The cam is configured to pivot relative to the central shaft when the central shaft is in abutment relative to a wall of the oblong orifice.

[0019] According to another embodiment feature, the first tooth is housed in a first tooth housing which is formed in the first segment. The first tooth is configured to abut in the first tooth housing by urging the first segment against the drum, when the central shaft is in abutment relative to a wall of the oblong orifice and the cam rotates around the central shaft.

[0020] According to a particular embodiment, the cam comprises a second tooth configured to mechanically drive the second segment. The second tooth is housed in a second tooth housing which is formed in the second segment. The second tooth is configured to come into abutment in the second tooth housing by urging the second segment against the drum, when the central shaft is in abutment relative to a wall of the oblong orifice and the cam rotates around the central shaft.

[0021] According to another particular embodiment, the braking lever comprises at least a first drive hook which is configured to mechanically engage the cam by tending to rotate the cam relative to the plate when the lever pivots relative to the plate.

[0022] According to a particular embodiment, the first drive hook is configured to mechanically engage the first drive portion, tending to rotate the cam relative to the plate when the lever pivots relative to the plate.

[0023] According to a particular embodiment, the braking lever comprises a second drive hook, the cam comprises a second drive portion. The second drive hook is configured to mechanically engage the second drive portion, tending to rotate the cam relative to the plate when the lever pivots relative to the plate.

[0024] According to a particular embodiment, the braking lever comprises a first longitudinal end and a second longitudinal end which is opposite the first longitudinal end. The brake lever is configured to pivot relative to the plate about its second longitudinal end when pulled at its first longitudinal end, the brake lever urging the first segment or the second segment against the drum via the cam drive system, during parking braking of the vehicle.

[0025] According to a particular embodiment, the drum brake comprises a reinforcement plate for the first segment, the reinforcement plate is configured to protect the first segment against wear by friction of the cam against the first segment.

[0026] According to another embodiment feature, the drum brake comprises a reinforcing plate for the second segment. The reinforcing plate is configured to protect the second segment against wear by friction of the cam against the second segment.

[0027] According to a particular embodiment, the plate comprises a first face and a second face opposite the first face. The segments are located on the first face of the plate. The lever is located on the second face. Preferably, the cam is located on the first face.

[0028] According to another embodiment feature, the drum brake comprises a second actuator which is an electromechanical actuator which comprises a geared motor. The second actuator is configured to pull on the braking lever to pivot the braking lever by urging the first segment or the second segment against the drum, during parking braking of the vehicle.

[0029] According to a particular embodiment, the first actuator is a hydraulic actuator. The first actuator is configured to be supplied with hydraulic braking fluid to urge the movement of the first segment and the second segment against the drum to brake the wheel.

[0030] According to a particular embodiment, during parking braking when the wheel is rotated backwards, the first longitudinal end of the brake lever is pulled with a traction force, the brake lever pivots around the second longitudinal end of the lever, the lever drives the cam drive system which drives the first segment against the drum, the first intermediate element transmits the force from the first segment to the second segment, the first segment and the second segment rotate in the same direction relative to the plate.

[0031] According to another particular embodiment, during service braking, the first actuator forces the first segment and the second segment apart, the first actuator exerts a first thrust force on the first longitudinal end of the first segment, the first segment pivots around the second longitudinal end of the first segment, the first segment rubs against the drum, the first actuator exerts a second thrust force opposite to the first thrust force on the first longitudinal end of the second segment, the second segment pivots around the second longitudinal end of the second segment, the second segment rubs against the drum. brief description of the figures

[0032] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate: • [Fig.l]: a schematic representation in exploded perspective of a simplex drum brake in service braking, according to an embodiment known from the state of the art; • [Fig.2]: a perspective representation of a drum brake according to a first embodiment, which is installed on a motorized road vehicle • [Fig.3]: a front view representation of a drum brake according to the first embodiment; • [Fig.4]: a partially sectioned cross-sectional view of a system cam drive of the brake according to the first embodiment; • [Fig.5]: a perspective representation of a cam of the cam drive system of the drum brake according to the first embodiment; • [Fig.6]: a perspective view of a lever of the cam drive system of the drum brake according to the first embodiment; • [Fig.7]: simplex operation of the drum brake according to the first mode of realization, in service braking; • [Fig.8]: the dual servo operation of the drum brake according to the first embodiment, in parking braking; • [Fig.9]: the operation of the cam drive system of the brake drum according to the first embodiment, during parking braking; • [Fig. 10]: a rear view representation of a drum brake according to a second embodiment; • [Fig.l 1]: a cross-sectional view of a brake cam drive system according to the second embodiment, in particular of detail A of [Fig.10].

[0033] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED description of an embodiment

[0034] [Fig. 2] represents a motorized road vehicle 1 which comprises a drum brake 2 according to the first embodiment of the invention which is installed around a hub 12 of the vehicle, to brake a wheel of the vehicle 1. The drum brake 2 comprises a drum 3 which is fixed to the wheel and a brake module which is fixed to a fixed part of the vehicle 1 such as a chassis 11 of the vehicle.

[0035] With joint reference to Figures 2 to 9, the drum brake 2 comprises a drum 3, a plate 20, a first braking segment 21, a second braking segment 23, a first actuator 5, a second actuator 7, a cam drive system 6, a lever 9. The drum brake 2 also comprises a first intermediate element 22, a reinforcing plate 26 of the first segment 21 and a reinforcing plate 26 of the second segment 23.

[0036] The drum brake 2 is configured to brake the wheel in simplex mode during service braking. During service braking, the first actuator 5 forces the first segment 21 and the second segment 23 apart from each other, each of which forces them against the drum 3. The drum brake 2 is configured to brake the wheel in dual servo mode during parking braking of the vehicle 1. During braking in dual servo mode, the first segment 21 and the first segment 23 move in particular in rotation in the same direction relative to the plate 20, the intermediate element 22 transmitting in particular a force from one of the segments 21, 23 to the other of the segments 21, 23.

[0037] The plate 20 serves as a support for the brake module, in particular for the segments 21, 23, the first actuator 5, the second actuator 7, the lever 9 and the cam drive system 6. The plate 20 comprises an insertion hole 25 for a vehicle hub. The plate 20 has substantially the shape of a disc hollowed out in its center around the insertion hole 25 of the hub. The plate 20 is substantially symmetrical in revolution around a direction of rotation XX which corresponds substantially to the longitudinal direction of the vehicle hub 12, when the brake 2 is installed on the vehicle 1.

[0038] In the present document, a direction of rotation XX is a direction which is parallel with the axis of revolution of the plate 20. The central axis XI-XI of the cam drive system is for example a direction of rotation. In the absence of specific specification to the contrary, an axial direction is a direction parallel to the longitudinal direction ZZ of the first actuator. An axial direction is also a direction parallel to the actuation direction of the first actuator 5 on the first segment 21 or on the second segment 23. The longitudinal axis ZI-ZI of the cam extends for example axially when the cam 8 is not inclined and the parking brake is not activated. A transverse direction is a direction orthogonal to the direction of rotation XX and to the axial direction. A radial direction is a direction of a ray of the plate 20 which is locally perpendicular to the direction of rotation XX.

[0039] The first braking segment 21 and the second braking segment 23 are connected to the plate 20 while being rotatable relative to the plate 20. The first braking segment 21 extends longitudinally between a first longitudinal end 21a which is located near the first actuator 5 and a second longitudinal end 21b which is located near the cam drive system 6. The second braking segment 23 extends longitudinally between a first longitudinal end 23a which is located near the first actuator 5 and a second longitudinal end 23b which is located near the cam drive system 6. When the segments 21, 23 are at rest, they extend for example transversely. The first segment 21 and the second segment 23 are configured to brake the wheel by friction against the drum 3, when they are actuated relative to the plate 20.

[0040] The reinforcing plate 26 of the first segment 21 covers the second longitudinal end 21b of the first segment. The reinforcing plate 26 of the first segment 21 is called the first reinforcing plate 26. The first reinforcing plate 26 is a first protective plate which is rigidly secured to the second longitudinal end 21b of the first segment. The first reinforcing plate 26 is for example fixed to the second longitudinal end 21b of the first segment. The first reinforcing plate 26 is configured to protect the first segment 21 against wear during friction of the cam drive system 6 against the first segment 21. In particular, the first reinforcing plate 26 is configured to protect the second longitudinal end 21b of the first segment against wear during friction of the cam 8 against the first segment 21.

[0041] The reinforcing plate 26 of the second segment 23 covers the second longitudinal end 23b of the second segment. The reinforcing plate 26 of the second segment 23 is called the second reinforcing plate 26. The second reinforcing plate 26 is a protective plate which is rigidly secured to the second longitudinal end 23b of the second segment. The second reinforcing plate 26 is for example fixed to the second longitudinal end 23b of the second segment. The second reinforcing plate 26 is configured to protect the second segment 23 against wear during friction of the cam drive system 6 against the first segment 23. In particular, the second reinforcing plate 26 is configured to protect the second longitudinal end 23b of the second segment against wear during friction of the cam 8 against the second segment 23.

[0042] The lever 9 is connected to the plate 20 while being pivotally movable relative to the plate 20 during parking braking of the vehicle 1. The lever 9 extends longitudinally longitudinally between a first longitudinal end 9a which is located near the first actuator 5 and a second longitudinal end 9b which is located near the cam drive system 6. The second longitudinal end 9b of the lever 9 is located substantially opposite the first actuator 5 relative to the hub insertion hole 25. The lever 9 also comprises a first drive hook 92 and a second drive hook 94 which are configured to mechanically engage the cam 8 of the cam drive system 6. When the lever 9 pivots relative to the plate 20, the lever 9 is configured to drive the cam 8 of the cam drive system 6. When parking braking the vehicle 1, the lever 9 is configured to be pulled at its first longitudinal end 9a and to pivot around its second longitudinal end 9b, driving the cam drive system 6.When parking braking the vehicle 1, the lever 9 is configured to pivot by urging the first segment 21 or the second segment 23 towards the drum 3 via the cam drive system 6.

[0043] The first intermediate element 22 comprises a connecting rod and a spring. The first intermediate element 22 is located near the first actuator 5, being located between the first actuator 5 and the insertion hole 25 of the hub. The first intermediate element 22 is located opposite the cam drive system 6 relative to the insertion hole 25 of the hub. The first intermediate element 22 extends axially between the first segment 21 and the second segment 23. The first intermediate element 22 connects the first longitudinal end 21a of the first segment to the first longitudinal end 23a of the second segment. The first intermediate element 22 is a member for incrementally compensating for play linked to the wear of the segment linings 21, 23. The first intermediate element 22 is configured to maintain a constant spacing between the segments 21, 23 at rest, taking into account the wear of the segments 21, 23.In dual servo mode, the first intermediate element 22 is configured to transmit a displacement of the first longitudinal end 21a of the first segment relative to the first end 23a of the second segment and vice versa, tending to move them parallel to each other relative to the plate 20.

[0044] The first actuator 5 is a hydraulic actuator. The first actuator 5 comprises a hydraulic chamber for containing a brake fluid, a first piston configured to push the first segment 21 and a second piston configured to push the second segment 23. The first actuator 5 is configured to be supplied with hydraulic brake fluid to urge a separation of the first segment 21 and the second segment 23 towards the drum 3 to brake the wheel. The first actuator 5 is also known as a “wheel cylinder”. The first actuator 5 is configured to brake the wheel in service braking of vehicle 1, by urging each of the first segment 21 and the second segment 23 by a hydraulic thrust force against the drum 3 to brake the wheel.

[0045] The second actuator 7 is an electromechanical actuator and the second actuator 7 comprises a geared motor. The second actuator 7 is configured to pull the lever 9 to pivot the lever 9 by urging the first segment 21 or the second segment 23 against the drum 3 via the cam drive system 6, during parking braking of the vehicle 1. The second actuator 7 is configured to urge the first braking segment 21 towards the drum 3 to brake the wheel, when the second actuator 7 pulls a brake cable 29 and pivots the lever 9 by driving the cam drive system 6. The second actuator 7 is configured to urge the second segment 23 towards the drum 3 during parking braking of the vehicle 1 to brake the wheel, when the second actuator 7 pulls a braking cable 29 and pivots the lever 9, driving the cam drive system 6.

[0046] The cam drive system 6 comprises a central shaft 60, the first drive hook 92, the second drive hook 94 and the cam 8. The lever 9 and the cam 8 of the cam drive system 6 are rotatable about the central axis Xl-Xl of the central shaft 60. The cam drive system 6 is configured to transform a rotational movement of the lever 9 about the central axis Xl-Xl of the central shaft 60 into an axial translational movement of the first segment 21 or the second segment 23 against the drum 3. The cam drive system 6 is configured to drive the first segment 21 or the second segment 23 against the drum 3, in parking braking of the vehicle 1.

[0047] The first drive hook 92 has a general lug shape. The first drive hook 92 extends longitudinally substantially parallel to the direction of the central axis Xl-Xl. The first drive hook 92 is configured to mechanically engage the cam 8 by tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20. More precisely, the first drive hook 92 is configured to mechanically engage the first drive portion 82 of the cam, by tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20.

[0048] The second drive hook 94 has a general lug shape. The second drive hook 94 extends longitudinally substantially parallel to the direction of the central axis Xl-Xl. The second drive hook 94 is configured to mechanically engage the cam 8 by tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20. More precisely Specifically, the second drive hook 94 is configured to mechanically engage the second drive portion 84 of the cam, tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20.

[0049] The cam 8 comprises a cam body 80 which has a general plate shape, the first drive portion 82, the second drive portion 84, a first tooth 83, a second tooth 85 and an oblong orifice 81. The cam 8 is preferably in one piece. The cam 8 is configured to rotate relative to the central axis XI-XI of the central shaft 60. The cam 8 is also configured to move perpendicular to the central axis XI-XI of the central shaft 60. The cam 8 is in particular configured to pivot relative to the central shaft 60 when the central shaft 60 is in abutment relative to a wall 81a of the oblong orifice. The cam 8 is configured to drive the second longitudinal end 21b of the first segment 21 or the second longitudinal end 23b of the second segment in axial translation against the drum 3, when the cam 8 is mechanically driven by the lever 9.

[0050] The oblong orifice 81 extends longitudinally along the longitudinal direction Zl-Zl of the cam. The oblong orifice 81 is substantially in the center of the body 80. The oblong orifice 81 is delimited by a wall 81a inside the body 80. The oblong orifice 81 has, for example, an elliptical-shaped contour. The oblong orifice 81 is a through orifice. The oblong orifice 81 is a passage orifice for the central shaft 60 of the cam drive system 6.

[0051] The cam drive system 6 comprises a first stop 87 of the central shaft relative to the cam 8. The first stop 87 is configured to stop a movement of the central shaft 60 relative to the cam 8 in the longitudinal direction Z1-Z1 of the cam. In the embodiments shown, the first stop 87 is formed by the wall 81a of the oblong orifice at a first longitudinal end of the oblong orifice 81.

[0052] The cam drive system 6 comprises a second stop 89 of the central shaft relative to the cam 8. The second stop 89 is configured to stop a movement of the central shaft 60 relative to the cam 8 in the longitudinal direction Zl-Zl of the cam. In the embodiments shown, the second stop 89 is formed by the wall 81a of the oblong orifice at a second longitudinal end of the oblong orifice 81 which is opposite the first longitudinal end of the oblong orifice 81 relative to the longitudinal direction Zl-Zl of the cam.

[0053] The central shaft 60 is preferably fixed relative to the plate 20. The central shaft 60 is preferably fixed to the plate 20. The central shaft 60 passes through the second longitudinal end 9b of the lever, the cam 8 extending through the oblong orifice 81 and the segments 21, 23. The central shaft 60 is configured to slide relative to the cam 8 in the oblong orifice 81, in particular along the longitudinal direction Zl-Zl of the cam. In particular, the central shaft 60 slides relative to the cam 8 in the oblong orifice 81 when the vehicle 1 is on a slope during parking braking. The central shaft 60 is configured to move relative to the oblong orifice 81 between the first stop 87 and the second stop 89, in particular coming into contact with the first stop 87 or the second stop 89 during parking braking. More specifically, the central shaft 60 is for example configured to slide inside the oblong orifice 81 relative to the cam 8 up to the first stop 87 or up to the second stop 89 during parking braking, being guided by the wall 81a of the oblong orifice in the longitudinal direction Z1-Z1 of the cam. In the rest position of the drum brake 2 and in the absence of a slope, the central shaft 60 is located substantially in the center of the oblong orifice 81.

[0054] The first drive portion 82 projects from the body 80 in the longitudinal direction Zl-Zl of the cam. The first drive portion 82 has a general tongue shape. The first drive portion 82 is configured to mechanically engage the lever 9 by tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20. More precisely, the first drive portion 82 is configured to be driven in rotation about the central axis XI-XI of the central shaft by the first drive hook 92, when the lever 9 pivots about the central axis XI-XI of the central shaft and the first drive hook 92 is in rotational abutment against the first drive portion 82.

[0055] The second drive portion 84 projects from the body 80 in the longitudinal direction Z1-Z1 of the cam. The second drive portion 84 is opposite the first drive portion 82 relative to the body 80 of the cam. The second drive portion 84 has a general tongue shape. The second drive portion 84 is configured to mechanically engage the lever 9 by tending to rotate the cam 8 relative to the plate 20 when the lever 9 pivots relative to the plate 20. More precisely, the second drive portion 84 is configured to be driven in rotation about the central axis XI-XI of the central shaft by the second drive hook 94, when the lever 9 pivots about the central axis XI-XI of the central shaft and the second drive hook 94 is in rotational abutment against the second drive portion 84.

[0056] The first tooth 83 projects from the body 80 substantially perpendicular to the body 80. The first tooth 83 extends substantially parallel to the central axis XI-XI of the central shaft. The first tooth 83 is for example substantially located in the middle of the body 80 in the longitudinal direction ZI-Z of the cam. The first tooth 83 is housed in a first tooth housing 61 which is located in the first segment 21. The first tooth 83 is configured to mechanically drive the first segment 21 by urging the first segment 21 against the drum 3. The first tooth 83 is in particular configured to come into abutment relative to the first tooth housing 61 by urging the first segment 21 against the drum 3, when the central shaft 60 is in abutment relative to a wall of the oblong orifice 81 and the cam 8 rotates around the central shaft 60. More precisely, the first tooth 83 is configured to come into abutment against the first tooth housing 61 by urging the first segment 21 against the drum 3, when the central shaft 60 is in abutment against the first stop 87 and the cam 8 has rotated around the central shaft 60. 85 projects from the body 80 substantially perpendicular to the body 80.The second tooth 85 extends substantially parallel to the central axis XI-XI of the central shaft. The second tooth 85 is for example substantially located in the middle of the body 80 in the longitudinal direction ZI-Z of the cam. The second tooth 85 is housed in a second tooth housing which is located in the second segment 23. The second tooth 85 is configured to mechanically drive the second segment 23, by urging the second segment 23 against the drum 3. The second tooth 85 is in particular configured to come into abutment relative to the second tooth housing by urging the second segment 23 against the drum 3, when the central shaft 60 is in abutment relative to a wall of the oblong orifice 81 and the cam 8 rotates around the central shaft 60.More specifically, the second tooth 85 is configured to abut against the second tooth housing by urging the second segment 23 against the drum 3, when the central shaft 60 is in abutment against the second stop 89 and the cam 8 has rotated around the central shaft 60.

[0058] With more specific reference to the first embodiment which is shown in Figures 2 to 9, the plate 20 comprises a first face and a second face opposite the first face. The first face is typically the internal face of the plate which is at least partially covered by the drum 3. The second face is typically a rear external face of the plate 20. The segments 21, 23 are located on the first face of the plate 20. The cam 8 is located on the first face. The lever 9 is located on the first face. The second actuator 7 is preferably located on the second face.

[0059] With more specific reference to the second embodiment which is shown in Figures 10 and 11, the plate 20 comprises a first face and a second face opposite the first face. The first face is typically the internal face of the plate which is at least partially covered by the drum 3. The second face is typically a rear external face of the plate 20. The segments 21, 23 are located on the first face of the plate 20. The lever 9 is located on the second face. The cam 8 is located on the first face. The second actuator 7 is preferably located on the second face.

[0060] [Fig.7] illustrates simplex service braking by a drum brake 2 according to the first embodiment or according to the second embodiment. The first actuator 5 forces the first segment 21 and the second segment 23 apart. The first actuator 5 exerts a first thrust force PI on the first longitudinal end 21a of the first segment. The first segment 21 pivots around its second longitudinal end 21b. The first segment 21 rubs against the drum 3 near its first longitudinal end 21a to brake the wheel. The first actuator 5 exerts a second thrust force P2 opposite the first thrust force PI on the first longitudinal end 23a of the second segment. The second segment 23 pivots around its second longitudinal end 23b. The second segment 23 rubs against the drum 3 near its first longitudinal end 23a to brake the wheel.

[0061] Figures 8 and 9 illustrate a dual servo parking brake by a drum brake 2 according to the first embodiment or according to the second embodiment. In parking braking, the wheel and the drum 3 are for example likely to be rotated backwards due to a slope of the road. When it is pulled on the first longitudinal end 9a of the brake lever with a tensile force P3, the brake lever 9 pivots about its second longitudinal end 9b, the lever 9 drives the cam drive system 6, the cam drive system 6 drives the first segment 21 or the second segment 23 against the drum 3. The first intermediate element 22 transmits the force from the first segment 21 to the second segment 23 or from the second segment 23 to the first segment 23.The first segment 21 and the second segment 23 rotated in the same direction relative to the plate 20, the intermediate element 22 transmitted a force from one of the segments 21, 23 to the other of the segments 21, 23.

[0062] With reference to Figures 1 to 9, when the first segment 21 is urged against the drum 3, the first drive hook 92 mechanically engages the first drive portion 82, the central shaft 60 comes for example into contact with the first stop 87, the cam 8 rotates around the central axis Xl-Xl of the central shaft, the first tooth 83 comes into abutment with the first tooth housing 61, urging the first segment 21 against the drum 3 according to the thrust force P4. The first segment 21 rotates around its first longitudinal end 21a, rubbing against the drum 3 to brake the wheel on the side of its second longitudinal end 21b. The first intermediate element 22 transmits the force from the first segment 21 to the second segment 23, between the first longitudinal end 21a of the first segment and the first longitudinal end 23a of the second segment. The second segment 23 rotates around its second longitudinal end 23b, rubbing against the drum 3 to brake the wheel on the side of its first longitudinal end 23a.

[0063] With reference to Figures 1 to 9, when the second segment 23 is urged against the drum 3, the second drive hook 94 mechanically engages the second drive portion 84, the central shaft 60 comes for example into contact with the second stop 89, the cam 8 rotates around the central axis XI-XI of the central shaft, the second tooth 85 comes into abutment with the second tooth housing, urging the second segment 23 against the drum 3. The second segment 23 rotates around its first longitudinal end 23a, rubbing against the drum 3 to brake the wheel on the side of its second longitudinal end 23b. The first intermediate element 22 transmits the force from the second segment 23 to the first segment 21, between the first longitudinal end 23a of the second segment and the first longitudinal end 21a of the first segment.The first segment 21 rotates around its second longitudinal end 21b, rubbing against the drum 3 to brake the wheel on the side of its first longitudinal end 21a.

[0064] Thanks to the drum brake 2 according to the invention, the service braking is stable and precise and the parking braking is particularly intense, while having a brake that is easy to manufacture and install and while limiting the mass and size of the vehicle brake 1.

[0065] The drum brake 2 is configured to brake the wheel in simplex mode by spreading the segments 21, 23 during service braking, which allows stable and precise braking of the wheel. The drum brake 2 is configured to brake the wheel in duo servo mode during parking braking, which allows particularly intense braking of the wheel.

[0066] The drum brake 2 tends to be more energy efficient and more responsive during parking braking than a drum brake 2 of known structure with equivalent braking power, which would stress the segments 21, 23 in spacing during parking braking.

[0067] The mass and size of the drum brake 2 are reduced compared to the mass and size of a drum brake 2 of known structure in which the lever 9 tends to force the segments 21, 23 apart. In particular, the size and mass of the plate 20, the segments 21, 23 and the first actuator 5 are likely to be further limited. Due to the reduced mass and size of the drum brake 2, the manufacture of the drum brake 2 is facilitated compared to a drum brake 2 of known structure.

[0068] The lever 9 and the cam drive system 6 are located opposite the first actuator 5 relative to the insertion hole 25 of the hub. This results in limited space requirement near the first actuator 5 and the insertion hole 25 of the vehicle hub, which is generally a crowded region of the brake 2. It is then easier to install the brake 2 around a hub 12 of the vehicle 1. More generally, the limited mass and space requirement of the drum brake 2 facilitate its installation in the vehicle 1.

[0069] By being located close to each other and in particular on the same side of the brake 2 relative to the insertion hole 25 of the hub, the first actuator 5 and the second actuator 7 are likely to be better and more easily protected mechanically and fluidically. In particular, by being located on an upper part of the drum brake 2, the first actuator 5 and the second actuator 7 are better protected against impacts, for example against stones, and splashes.

[0070] Of course, various modifications can be made by those skilled in the art to the invention which has just been described without departing from the scope of the disclosure of the invention.

[0071] Alternatively, the first intermediate element 22 comprises a connecting rod and a holding spring which are strictly parallel to each other. Additionally or alternatively, the drum brake 2 comprises a second intermediate element. Additionally or alternatively, the drum brake 2 comprises at least one holding spring which is configured to bias the segments 21, 23 towards each other when the drum brake 2 is in a rest position.

[0072] Alternatively, the drum brake 2 is devoid of a reinforcing plate 26. Alternatively, the drum brake 2 comprises a single reinforcing plate 26 which covers the second end of the first segment 21 and that of the second segment 23, being located between the cam 8 and the first segment 21 and the cam 8 and the second segment 23.

[0073] Alternatively, the first actuator 5 is an electromechanical actuator. The first actuator 5 comprises a geared motor.

[0074] Alternatively, the second actuator 7 is a hydraulic actuator. The second actuator 7 comprises a hydraulic chamber. As a further alternative, the second actuator 7 is replaced by a handbrake lever 9 in a passenger compartment of the vehicle 1.

[0075] Alternatively, the cam drive system 6 comprises a single drive hook 92, 94, a single drive portion 82, 84 and / or a single tooth 83, 85.

[0076] As a variant, the braking lever 9 is devoid of a second drive hook 94. As a further variant, the lever 9 comprises at least one projecting portion which has a shape distinct from a hook, instead of one of the drive hooks 92, 94.

[0077] Alternatively, the oblong orifice 81 has a contour having a shape different from that of an ellipse.

[0078] Alternatively, the first stop 87 is distinct from the wall 81a of the oblong orifice 81. Alternatively, the second stop 89 is distinct from the wall 81a of the oblong orifice 81.

[0079] Alternatively, the stop of the first tooth 83 is distinct from the housing wall of the first tooth.

[0080] As a variant, the drum brake 2 is devoid of a second tooth 85. As a variant, the stop of the second tooth 85 is distinct from the housing wall of the second tooth.

[0081] As a variant, the stacking of the lever 9, the cam 8 and the segments 21, 23 around the central shaft 60 is modified compared to that of the first embodiment and that of the second embodiment, for example the lever 9 and the cam 8 can be between the segments 21, 23 and the plate 20. LIST OF DIGITAL REFERENCES

[0082] 1: Vehicle

[0083] 2: Brake

[0084] 3: Drum

[0085] 4: Fixed point

[0086] 5: First actuator

[0087] 6: cam drive system

[0088] 7: Second actuator

[0089] 8: Came

[0090] 9: Lever

[0091] 9a: First longitudinal end of the lever

[0092] 9b: Second longitudinal end of the lever

[0093] 11: Chassis

[0094] 12: Hub

[0095] 20: Plateau

[0096] 21: First segment

[0097] 21a: First longitudinal end of the first segment

[0098] 21b: Second longitudinal end of the first segment

[0099] 22: First intermediate element

[0100] 23: Second segment

[0101] 23 a: First longitudinal end of the second segment

[0102] 23b: Second longitudinal end of the second segment

[0103] 24: Reaction rod

[0104] 25: Hub insertion hole

[0105] 26: Segment reinforcement plate

[0106] 29: Brake cable

[0107] 60: Central shaft of the cam drive system

[0108] 61: First tooth housing

[0109] 80: Cam body

[0110] 81: Oblong orifice [YES] 81 a: Wall of the oblong orifice

[0112] 82: First portion of training

[0113] 83: First tooth

[0114] 84: Second portion of training

[0115] 85: Second tooth

[0116] 87: First stop

[0117] 89: Second stop

[0118] 92: First training hook

[0119] 94: Second training hook

[0120] XX: direction of the axis of rotation of the drum

[0121] Xl-Xl: central axis of the cam drive system

[0122] ZZ: axial direction

[0123] Zl-Zl: longitudinal axis of the cam and the oblong orifice

[0124] PI: first pushing effort

[0125] P2: second pushing effort

[0126] P3: Traction force

[0127] P4: Thrust force

Claims

Claims

1. Drum brake module (2) for a wheel of a motorized road vehicle (1), comprising: a plate (20), a first braking segment (21) and a second braking segment (23) which are connected to the plate (20) while being rotatable relative to the plate (20), a first actuator (5) configured to urge the first braking segment (21) and the second braking segment (23) apart towards a drum (3) to brake the wheel during service braking of the vehicle (1), a braking lever (9) configured to pivot relative to the plate (20) during parking braking of the vehicle (1), the drum brake (2) being configured to brake the wheel in dual servo mode during parking braking of the vehicle (1), during braking in dual servo mode, the first segment (21) and the first segment (23) being in particular rotatable in the same direction relative to the plate (20),an intermediate element (22) of the brake module transmitting in particular a force from one of the segments (21, 23) to the other of the segments (21, 23), characterized in that the brake module comprises a cam drive system (6) for parking braking of the wheel, the cam drive system (6) comprising a cam (8), the lever (9) being configured to pivot while driving the cam (8), the cam (8) urging the first segment (21) or the second segment (23) against the drum (3), during parking braking of the vehicle (1).,

2. Drum brake module (2) according to the preceding claim, in which the cam (8) comprises at least a first drive portion (82), the first drive portion (82) being configured to mechanically engage the lever (9) by tending to rotate the cam (8) relative to the plate (20) when the lever (9) pivots relative to the plate (20).

3. A drum brake module (2) according to any preceding claim, wherein the cam (8) comprises a first tooth (83) configured to mechanically drive the first segment (21), the first tooth (83) being configured to mechanically drive the first segment (21) by urging the first segment (21) against the drum (3).

4. Drum brake module (2) according to any one of the preceding claims, in which the cam (8) comprises an orifice oblong (81) for passage of a central shaft (60) of the cam drive system (6), in which the central shaft (60) is configured to slide inside the oblong orifice (81) relative to the cam (8), the cam (8) being configured to pivot relative to the central shaft (60) when the central shaft (60) is in abutment relative to a wall of the oblong orifice (81).

5. Drum brake module (2) according to the preceding claim and according to claim 3, wherein the first tooth (83) is housed in a first tooth housing (61) which is formed in the first segment (21), wherein the first tooth (83) is configured to abut in the first tooth housing (61) by urging the first segment (21) against the drum (3), when the central shaft (60) is in abutment relative to a wall of the oblong orifice (81) and the cam (8) rotates around the central shaft (60).

6. Drum brake module (2) according to the preceding claim, wherein the cam (8) comprises a second tooth (85) configured to mechanically drive the second segment (23), the second tooth (85) being housed in a second tooth housing which is formed in the second segment (23), wherein the second tooth (85) is configured to come into abutment in the second tooth housing by urging the second segment (23) against the drum (3), when the central shaft (60) is in abutment relative to a wall of the oblong orifice (81) and the cam (8) rotates around the central shaft (60).

7. A drum brake module (2) according to any preceding claim, wherein the lever (9) comprises at least one first drive hook (92) which is configured to mechanically engage the cam (8) by tending to rotate the cam (8) relative to the plate (20) when the lever (9) pivots relative to the plate (20).

8. Drum brake module (2) according to the preceding claim and according to claim 2, in which the first drive hook (92) is configured to mechanically engage the first drive portion (82), tending to rotate the cam (8) relative to the plate (20) when the lever (9) pivots relative to the plate (20).

9. Drum brake module (2) according to the preceding claim, wherein the lever (9) comprises a second drive hook (94), the cam (8) comprising a second drive portion (84), wherein the second drive hook (94) is configured to mechanically engage the second drive portion (84), tending to rotate the cam (8) relative to the plate (20) when the lever (9) pivots relative to the plate (20).

10. A drum brake module (2) according to any one of the preceding claims, wherein the lever (9) comprises a first longitudinal end (9a) and a second longitudinal end (9b) which is opposite the first longitudinal end (9a), wherein the lever (9) is configured to pivot relative to the plate (20) about its second longitudinal end (9b) when pulled at its first longitudinal end (9a), the lever (9) urging the first segment (21) or the second segment (23) against the drum (3) via the cam drive system (6) during parking braking of the vehicle (1).

11. Drum brake module (2) according to any one of the preceding claims, wherein the drum brake (2) comprises a reinforcing plate (26) of the first segment (21) and / or the second segment (23), the reinforcing plate (26) being configured to protect the first segment (21) and / or the second segment (23) against wear by friction of the cam (8) against the first segment (21) and / or the second segment (23).

12. Drum brake module (2) according to any one of the preceding claims, in which the plate (20) comprises a first face and a second face opposite the first face, the segments (21, 23) being located on the first face of the plate (20), the lever (9) being located on the second face, the cam (8) preferably being located on the first face.

13. A drum brake module (2) according to any preceding claim, wherein the drum brake (2) comprises a second actuator (7) which is an electromechanical actuator which comprises a geared motor, the second actuator (7) being configured to pull the lever (9) to pivot the lever (9) by urging the first segment (21) or the second segment (23) against the drum (3), during parking braking of the vehicle (1).

14. A drum brake module (2) according to any preceding claim, wherein the first actuator (5) is a hydraulic actuator, the first actuator (5) being configured to be supplied with hydraulic brake fluid to urge the movement of the first segment (21) and the second segment (23) against the drum (3) to brake the wheel.

15. Drum brake module (2) according to claim 10, wherein in parking braking when the wheel is rotated rearwardly, the first longitudinal end (9a) of the brake lever is pulled with a tensile force (P3), the brake lever (9) pivots around the second longitudinal end (9b) of the lever, the lever (9) drives the cam drive system (6) which drives the first segment (21) against the drum (3), the first intermediate element (22) transmits the force from the first segment (21) to the second segment (23), the first segment (21) and the second segment (23) rotate in the same direction relative to the plate (20).

16. Drum brake module (2) according to any one of the preceding claims, wherein during service braking, the first actuator (5) forces the first segment (21) and the second segment (23) apart, the first actuator (5) exerts a first thrust force (P1) on the first longitudinal end (21a) of the first segment, the first segment (21) pivots around the second longitudinal end (21b) of the first segment, the first segment (21) rubs against the drum (3), the first actuator (5) exerts a second thrust force (P2) opposite the first thrust force (P1) on the first longitudinal end (23a) of the second segment, the second segment (23) pivots around the second longitudinal end (23b) of the second segment, the second segment (23) rubs against the drum (3).

Images