WO2023208916A1

WO2023208916A1 - Drum brake for a motor vehicle

Info

Publication number: WO2023208916A1
Application number: PCT/EP2023/060781
Authority: WO
Inventors: Philippe EBLE; Ludovic LEVASSORT; Cédric GUIGNON; Cédric LEBOISNE; Bastien ELMERICH
Original assignee: Hitachi Astemo France
Priority date: 2022-04-27
Filing date: 2023-04-25
Publication date: 2023-11-02
Also published as: FR3135117B1; FR3135117A1

Abstract

The invention relates to a drum brake comprising a disk-shaped plate having an inner face to which a wheel cylinder and a bearing element, which bearing element is referred to as a fixed point bearing element, are attached at diametrically opposite positions, a first and a second segment, the drum brake having a second actuator comprising a parking brake lever (21) for immobilising the vehicle, which lever (21) is carried by the core of a segment and has one end that is rotatably linked to a first end of the core and another free end (23) to which an end of a brake cable (5) is attached, which brake cable, when under tension, pulls the free end of the lever (21) causing the lever to rotate (21) in order to separate the segments, the brake (1) having means for blindly installing the brake cable (5), the means comprising a through-opening formed in the plate, means for guiding the brake cable (5) made up of a sheath such as a coil spring (26) extending between the opening in the plate and the free end of the lever (21), and means for supporting the guide means. The invention is characterised in that the support means are made up of a U-shaped support element (27), the coil spring (26) being carried in the space defined between the arms of the U.

Description

Description Title of the invention: Motor vehicle drum brake

[0001] The invention relates to a drum brake comprising a disc-shaped plate having an internal face to which are fixed a wheel cylinder and a support member called a fixed point, at diametrically opposite positions, a first and a second segment comprising respectively a core to the outer edge of which is fixed a sole usually called a cylindrically bent sheet metal rim which carries a braking lining, each core comprising one end resting on a piston of the wheel cylinder and another end resting on the fixed point, the drum brake comprising a second actuator comprising a parking brake lever which allows the vehicle to be immobilized, this lever being carried by the core of a segment, and has an end linked in rotation at a first end of the core, and another free end to which is fixed one end of a brake cable, which when put in tension, pulls the free end of the lever, causing a rotation of the lever in order to separate the segments, the brake comprising means allowing the blind mounting of said brake cable, said means comprising a through hole made in the plate, means for guiding said brake cable consisting of a sheath such as a helical spring extending between the plate orifice and the free end of the lever as well as support means for said guide means.

[0002] The invention also relates to a method of manufacturing a drum brake as well as a method of blindly assembling a brake cable on an actuating lever of a drum brake according to the invention.

[0003] The field of the invention is the automotive field and more particularly a drum brake for a motor vehicle.

[0004] STATE OF THE ART

[0005] A drum brake is a braking member which is arranged in a vehicle to slow down or even block the rotation of the wheel by friction. Thus, a drum brake of this type can be used as a service brake to slow down or stop the vehicle, and also as a parking brake to ensure immobilization of the parked vehicle.

[0006] Such a drum brake comprises a fixed plate having an internal face on which are fixed a wheel cylinder and a support member called a fixed point, at diametrically opposite positions. This plate carries a first and a second segments having ends recalled to bear on the wheel cylinder and on the fixed point by two springs to grip one and the other. The first segment comprises a sheet metal core having the shape of a crown portion, to the outer edge of which is welded or crimped a sole usually called a cylindrically bent sheet metal rim which carries a braking lining. This core has one end resting on a piston of the wheel cylinder, and another end resting on the fixed point. The second segment has the same general structure.

[0007] These segments are movable radially to be pressed against an internal face of a rotating wheel drum so as to generate a braking torque. The wheel cylinder includes a chamber closed by two pistons which move apart when the hydraulic pressure increases, to separate the ends of the segments. Additionally, a wear compensation link runs along the wheel cylinder with one end resting on a lever carried by the first segment and another end resting on the core of the second segment when the brake is at rest. This link incorporates a mechanism which increases its length as the linings wear, so that the travel of the brake control remains unchanged over the life of the brake.

[0008] A lever carried by the core of the segment is actuated by a second actuator which controls the parking brake. This lever has one end linked in rotation by a connection to a first end of the core, and another free end to which a brake cable head is secured. This lever rests near the connection on the end of the link. When the cable is put under tension, it pulls the free end of the lever which then moves away from the rim, to press on the link in order to spread the segments so as to press them against the drum.

[0009] After mounting a brake of this type on a vehicle, the coupling of the cable to the lever is carried out blindly, the plate being in place in the drum. This assembly is ensured by first engaging the front end of this cable fitted with an end piece, through an external face of the plate, in a hole provided for this purpose in the plate which is located approximately opposite of the second segment. This end of the cable is then routed towards the end of the lever to be fixed there using guide means. Continuing this path, the end of the cable is fixed on the end of the lever through a passage hole provided on said end. [0010] Although such an arrangement makes it easier to blindly mount the brake cable, it still has drawbacks. Indeed, the guide means can consist of a helical spring through which the cable is engaged to come to the lever as has been described in US-A-4753325.

[0011] However, the use of the helical spring as guiding means poses problems linked to its fixing in the orifice of the plate as well as to the quality of the guidance in the travel zone between the orifice of the plate and the end of the lever. The relative “flexibility” of the spring between the engagement hole and the lever can cause difficulties to the extent that the end of the cable can come up against the spring and deform it, hindering correct and rapid guiding.

[0012] We have therefore proposed in FR-A-2772704 guide means comprising a conduit fixed relative to the plate and one end of which is housed in the orifice of the plate and the other end is linked to one end of a second conduit consisting of a helical spring whose other end is linked to the lever.

[0013] Likewise in FR-A-2841619 we have described means for guiding the brake cable comprising a helical spring extending between the orifice of the plate and the end of the lever, as well as a cylindrical element consisting of two gutter-shaped parts which, when joined, form a passage to hold the spring.

[0014] Such guiding means make it possible to resolve the problems linked to flexibility and the risk of jamming of the helical spring but requires for this purpose the use and installation on the plate and the lever of elements such as a conduit, which complicates the manufacture of the brake, in particular the mounting of the spring in said conduit, and therefore increases the manufacturing cost.

[0015] STATEMENT OF THE INVENTION

[0016] The present invention therefore aims to provide a drum brake making it possible to overcome these drawbacks. In particular, the subject of the invention is a drum brake in which the risks of blocking the front end of the cable in the helical spring are limited, while being simpler to manufacture and implement.

[0017] For this purpose, the subject of the invention is a drum brake comprising a disk-shaped plate having an internal face to which are fixed a wheel cylinder and a support member called a fixed point, at diametrically positioned positions opposite, a first and a second segments respectively comprising a core to the outer edge of which is fixed a sole usually called a cylindrically bent sheet metal rim which carries a braking lining, each core comprising one end resting on a piston of the wheel cylinder and another end resting on the fixed point, the drum brake comprising a second actuator comprising a parking brake lever which allows the vehicle to be immobilized, this lever being carried by the core of a segment, and has one end linked in rotation to a first end of the core, and another free end to which is fixed one end of a brake cable, which when put in tension, pulls the free end of the lever, causing a rotation of the lever in order to separate the segments, the brake comprising means allowing the blind mounting of said brake cable, said means comprising a through hole made in the plate, means for guiding said brake cable consisting of a sheath such as a helical spring extending between the plate orifice and the free end of the lever as well as support means for said guide means, characterized in that the support means consist of a U-shaped support element of which one of the branches is 'extends substantially parallel to the internal face of the plate and the core extends substantially perpendicular to said internal face of the plate, the open face of said holding element being oriented towards the center of the plate, the helical spring being carried in space defined between the branches of the U.

[0018] Very advantageously, during the manufacture of the brake according to the invention, the helical spring as guide means can be fixed with its ends on the one hand in the orifice of the plate then at the level of the lever and can then simply be slipped into the support element between the branches of said U-shaped support element. The assembly of the helical spring is thus much simpler to implement than when the spring is engaged through a conduit or under a retaining cover.

[0019] Furthermore, according to a preferred embodiment, the U-shaped support element has a core and a branch of U consisting respectively of a wall and of which the other branch of the U is defined by at least one tongue, preferably two, extending from the core of the U-shaped element facing the other branch.

[0020] Advantageously, the branch made up of tabs allows flexibility in maintaining the helical spring, which facilitates the guiding of the cable during blind assembly and also allows the movement of the helical spring when the lever is actuated parking brake control.

[0021] The support element is fixed to the plate, preferably on the support member, by for example by screwing. For this purpose, the support element has a fixing tab, fixed to the support member.

[0022] Thus, during blind assembly of the brake cable, these support means make it possible to maintain the helical spring along a precise portion of trajectory, in particular preventing deformation of the spring when the cable passes at the level of the bent portion of the brake cable. the trajectory at the exit of the plate orifice which gives said spring thus constrained and held in position a certain "rigidity" so that, when guiding the end of the parking brake cable in said spring, the latter cannot deform despite its elastic nature even when the end of the cable abuts against said spring. We therefore avoid jamming the end of the brake cable and thus promote easy passage of the cable in the helical spring.

[0023] Guiding the cable from the plate orifice towards the lever is thus facilitated and favored, using these support means, which makes blind mounting easier on a brake actuation lever. motor vehicle drum, a brake cable without the need for guide parts that are too rigid or bulky to mount on the plate.

Preferably, the helical spring has at one end a fixing tip in the plate orifice and its opposite end is fixed on the end of the lever at the level of the means for fixing the head of the brake cable. The trajectory thus defined for the helical spring presents at the outlet of the orifice of the plate a substantially bent portion causing the helical spring to extend along the face of the plate to the end of the lever.

[0025] In order to promote the maintenance of said bent portion, according to a preferred shape, the U-shaped support element extends asymmetrically relative to its point of attachment on the support member which is substantially in the central position between the plate hole and the end of the lever. Thus, the fixing tab of the support element extends at one end of said support element and the latter thus extends mainly on the plate orifice side, which makes it possible to better maintain the bent portion to promote the guiding of the head of the brake cable inside this bent portion. In particular, the risk of deformation of the helical spring is avoided when the bent portion passes through the brake cable head.

[0026] Thus, advantageously, when the end piece or head of the brake cable is engaged in the front, inlet end of the helical spring at the level of the plate orifice, it can pass the bent portion of said spring without deforming it too much, which promotes good guidance.

These support means thus formed are fixed to the plate by screwing, welding or any other appropriate means. [0028] According to a preferred embodiment, the actuating lever of a drum brake is formed by an oblong plate of thickness "e" and of longitudinal axis X, intended to extend, once mounted in the drum brake, in a vertical transverse plane. One end of the actuating lever is mounted linked in rotation by a connection to a first end and its other free end is secured to a front end or head of a parking brake control cable. Means for fixing the end of the brake control cable are arranged at the biasing end of the actuation lever, the traction exerted on the brake cable causing the actuation lever to pivot at its opposite end and actuating , therefore, the parking brake. The means for fixing the end of the brake cable arranged at the free end of the lever may consist of a U-shaped retaining channel, for fixing the end of the parking brake control cable.

[0029] According to a first embodiment of the invention, the retaining chute is made in one piece with the actuating lever. Thus, the end of the lever is preferably cut so as to present a tongue extending axially projecting, which is folded so that it defines on one face of this lever, that facing the plate, a chute of retainer of U-shaped cross section whose first free branch is parallel to a second branch constituted by the lever.

According to a second embodiment, it is possible to provide a part with a U-shaped cross section attached to the end of the lever and fixed thereto by any appropriate means such as by riveting to form said chute.

Preferably, the retaining chute has an internal transverse dimension equal to or greater than that of the cable and less than the external diameter of the cable head.

[0032] Advantageously, the free branch of the retaining channel formed by the end of the tongue for example, is defined so as to form a ramp making it possible to guide the head of the brake cable during assembly of the brake cable .

[0033] In order to promote the correct positioning of the brake cable head in the U-shaped fold or retaining channel of the lever, it is also possible to provide on the lever a means for holding the brake cable head to the level of the chute, said holding means being movably mounted between a first position for closing the passage of the brake cable head and a second clearance position in which the brake cable head can pass, return means elastic bringing said means for maintaining the erased position towards the closed position, so that said holding means exerts a thrust against the head of the brake cable, which, once the rear end of the retaining chute has been reached, is held abutting at the rear of said chute.

[0034] Preferably this holding means consists of a leaf spring having at least one leaf portion extending substantially parallel to the retaining chute and above it, connected by a bent portion to a blade portion extending across the retaining chute at the end thereof and thus closing the passage after said chute. The leaf spring is carried by a fixing plate on the lever.

[0035] The invention also proposes a method of manufacturing said brake according to the invention, characterized in that the helical spring is fixed with its ends on the one hand in the orifice of the plate then at the level of the lever and is then slid in the support element between the branches of said U-shaped support element.

As already mentioned, after mounting a brake of this type on a vehicle, the fixing of the parking brake control cable to the lever is carried out blindly, the plate being in place in the drum. The invention also relates to a method of blindly assembling a brake cable on a drum brake according to the invention, characterized in that the head of the brake cable is engaged from the external face of the plate , in an orifice in the plate then this head of the brake cable is then guided by guide means such as a helical spring carried by the plate on the side of its internal face, towards the free end of the lever to be fixed there, the cable head then engaging in the retaining chute arranged at the end of the lever until it is housed after the rear end of said chute, the head being retained abutting against said rear end of said chute.

[0037] BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will appear during reading of the detailed description which follows, for the understanding of which we will refer to the appended drawings which represent:

[0039] [Fig. 1] a plan view of a drum brake according to the invention, intended to be mounted on a motor vehicle wheel;

[0040] [Fig. 2] a perspective view of the guiding means of a blind assembly arrangement;

[0041] [Fig. 3] a perspective view of the parking brake lever and the brake cable fixing means according to the invention; [0042] [Fg. 4] a perspective view of the end of the lever of Figure 3

[0043] [Fig. 5A] a sectional view of the end of the lever of Figure 4 according to a first step of mounting a brake cable;

[0044] [Fig. 5B] a sectional view of the end of the lever of Figure 4 according to a second step of mounting a brake cable;

[0045] [Fig. 5C] a sectional view of the end of the lever of Figure 4 according to a third step of mounting a brake cable.

[0046] A drum brake 1 according to the invention is shown in Figure 1. Such a drum brake

1 comprises a fixed plate 2 having an internal face to which are fixed a wheel cylinder 6 and a support member called fixed point 7, at diametrically opposite positions. This tray

2 carries a first and a second segments 3 and 4 having ends recalled to bear on the wheel cylinder 6 and on the fixed point 7 by two springs 8 and 9 to grip them both. The first segment 3 comprises a core 12 of sheet metal having the shape of a crown portion, to the outer edge of which is welded or crimped a sole usually called rim 13 of cylindrically bent sheet metal which carries a braking lining 14. This core 12 comprises one end 15 resting on a piston of the wheel cylinder 6, and another end 16 resting on the fixed point 7. The second segment 4 has the same general structure.

These segments 3 and 4 are movable radially to be pressed against an internal face of a rotating wheel drum so as to generate a braking torque. The wheel cylinder 6 comprises a chamber closed by two pistons which move apart when the hydraulic pressure increases, to separate the ends of the segments 3, 4. Additionally, a wear compensation link 17 runs along the wheel cylinder 6 in having one end 18 resting on a lever 21 carried by the first segment and another end 19 resting on the core of the second segment when the brake is at rest. This link 17 incorporates a mechanism which increases its length as the linings wear, so that the stroke of the brake control remains unchanged during the life of the brake.

A lever 21 carried by the core 12 of segment 3 is actuated by a second actuator which controls the parking brake. This lever 21 has one end linked in rotation by a connection 22 to a first end of the core 12, and another free end 23 to which is secured a brake cable head not visible in Figure 1. This lever 21 is in support in the vicinity of the connection 22 on the end 18 of the link 17. When the cable is put under tension, it pulls the free end 23 of the lever 21 which then moves away from the rim 13, to press on the link 17 in order to spread the segments 3 and 4 so as to press them against the drum.

[0049] After mounting a brake of this type on a vehicle, the coupling of the cable to the lever 21 is carried out blindly, the plate 2 being in place in the drum. This assembly is ensured by first engaging the front end of this cable 5 provided with an end piece 51, through an external face of the plate 2, in a through hole 24 made in the plate which is located approximately opposite each other. -screw of the second segment 4. This end of cable 5 is then routed towards the end 23 of the lever to be fixed there using guide means 26. Continuing this path, the end of cable 5 is fixed on the end 23 of the lever 21 through a passage orifice arranged on said end.

[0050] In particular the means for actuating the drum brake for parking according to the invention are shown in Figure 2. We can see the actuation lever 21 having at its biasing end 23, fixing means of the end of a brake cable such as a tab folded into a U to form a retaining channel 20 of the end of a parking brake control cable 5.

As already mentioned, after mounting a brake of this type on a vehicle, the coupling of the parking brake control cable to the lever 21 is carried out blindly, the plate 2 being in place in the drum. This assembly is ensured by first engaging the front end of this cable 5 provided with a head or end piece 51, through an external face of the plate 2, in a hole 24 provided for this purpose which is located approximately opposite opposite the second segment 4. This end of cable 5 is then guided by guide means such as a helical spring 26 carried by the plate 2 on the side of its internal face, towards the end 23 of the lever 21 to to be fixed.

[0052] Thus, in the example shown, the actuation lever 21 of a drum brake according to the invention is formed by an oblong plate of thickness "e" and of longitudinal axis extend, once mounted in the drum brake, in a transverse vertical plane as can be seen in Figure 1. One end of the actuating lever 21 is mounted linked in rotation by a connection at a first end and its other end free 23 is secured to a front end or head 51 of a parking brake control cable 5.

This free end 23 is cut so as to present a tongue 231 extending in an axial projection, which is folded in such a way that it defines on one face of this lever 21 a retaining chute 20 of U-shaped cross section The retaining chute 20 consists of the tongue 231 folded into a U so as to form a first free branch parallel to a second branch constituted by lever 21.

[0054] It is possible to provide a part with a U-shaped cross section attached to the end of the lever 21 and fixed thereto by any appropriate means such as by riveting to form said retaining chute 20.

The free branch of the retaining chute 20 formed by the end of the tongue 231 is defined so as to form a ramp 232. The retaining chute 20 has an internal transverse dimension equal to or greater than that of the cable 5 and less than the external diameter of the head 51 of the cable 5.

The parking brake control cable 5 introduced onto the face of the plate 2 through the orifice 24 is guided through the helical spring 26 to the free end 23 of the lever 21.

[0057] This arrangement therefore comprises, as means for guiding the brake cable 5, a helical spring 26, preferably with non-contiguous turns, which extends between the orifice 24 of the plate 2 and the biasing end 23 of the lever 21 and more precisely at the level of the retaining chute 20.

[0058] Thus, the helical spring 26 has an end 261 mounted in a ring 262 which is fixable in the orifice 24 and whose other end 263 is fixed on the biasing end 23 of the lever 21 so that said end 263 of the helical spring 26 opens substantially at the level of the retaining chute 20. However, the interior transverse dimension of the retaining chute 20 being less than the exterior diameter of the head 51 of the brake cable 5, it is provided that the guide means allow the engagement of the head 51 above the retaining chute 20, guided by the ramp 232 until said head 51 reaches the opposite end of the retaining chute 20 where once the ramp 232 has passed the head 51 which is no longer retained by the ramp 232 comes into abutment behind the end of the retaining chute 20 thus blocking the cable 5 in the retaining chute and on the lever 21.

[0059] In order to facilitate the guiding of the head 51 of the parking brake control cable on the ramp 232, a cover 10 is provided fixed on the so-called free loading end 23 of the lever 21, this cover 10 covering the part open of the retaining chute 20 and comprising at one end an annular shaped part 101 on which the end 263 of the helical spring 26 is fixed. The cover 10 is thus mounted on the lever 21 so that the annular part 101 provided with the helical spring 26 is positioned at the so-called inlet end 201 of the retaining chute 20 allowing the guided engagement of the head 51 of the cable brake control parking 5.

[0060] Advantageously, the head 51 of the parking brake control cable of a dimension greater than that of the retaining chute 20 slides on the ramp 232, therefore above the retaining chute 20, but retained by the cover 10 and this, until the ramp 232 ceases, the head 51 of brake cable 5 is housed after the rear end 202 of the chute 20, abutting against it while the cable 5 is housed at the bottom of the retaining chute 20.

[0061] Thus, the head 51 of the brake cable 5 is engaged by the orifice 24 through the ring 261, is guided through the helical spring 26 to its opposite end where it is then engaged at the level of the retaining chute 20 until it abuts at the rear of said retaining chute 20. We can then exert traction on the cable 5 to cause the lever 21 to rotate to actuate the parking brake.

[0062] In order to promote this engagement of the head 51 of the brake cable 5 and in particular its sliding along the ramp 232 for the purpose of fixing on the retaining chute 20, the cover 10 is positioned so that the annular part 101 on which the helical spring 26 is fixed allows it to open substantially opposite the retaining chute 20.

[0063] The blind mounting arrangement also includes means for supporting said helical spring 26 allowing simple installation of the spring and flexible holding of said spring 26 at least on a portion of the path between the orifice 24 of the plate 2 and the biasing end 23 of the lever 21, so as to help and promote the guiding of the brake cable 5 in the helical spring 26 during blind assembly while promoting the actuation of the parking brake lever 21.

[0064] These support means consist of a support element 27 having substantially a U shape, one branch of the U 272 and the core 271 being respectively constituted by a wall and the other branch of the U being defined by at least one tongue 273, preferably two, 273, 274 extending from the core 271 of the U-shaped element 27 facing the other branch 272. This support element 27 is positioned between the orifice 24 of the plate 2 and the biasing end 23 of the lever 21, so that the solid branch 272 of the support element 27 extends substantially parallel to the face of the plate 2, the core 271 of said support element 27 extending substantially perpendicular to said face of the plate 2. In this way, during the manufacturing assembly of the brake, the helical spring 26 is fixed with its ends on the one hand in the orifice 24 of the plate then at the level of the lever 21 and can then be slipped into the support element 27 between the branches 272; 273, 274 of said U-shaped support element 27. The mounting the spring is thus much simpler to implement than when the spring is engaged through a conduit or under a retaining cover.

The support element 27 is fixed to the plate 2, preferably on the support member 7, for example by screwing. For this purpose, the support element 27 has a fixing tab 275.

As already mentioned, the helical spring 26 has at the outlet of the orifice 26 of the plate a substantially bent portion causing the spring 26 to extend along the face of the plate 2 up to the end 23 of the lever 21 and more precisely opposite the retaining chute 20 of said lever 21. In order to promote the maintenance of said bent portion, according to a preferred shape, the U-shaped element 27 extends asymmetrically relative to its point fixing on the support member 7 which is substantially in the central position between the orifice of the plate 24 and the end 23 of the lever. Thus, the support element is more active on the orifice 24 side of the plate 2, better maintaining the bent portion to promote the guiding of the head of the brake cable inside this bent portion. In particular, the risks of deformation of the spring 26 are avoided during the passage of the bent portion by the head 51 of the brake cable 5.

[0067] In order to promote the correct positioning of the head 51 of the brake cable in the U-shaped fold or retaining channel 20 of the lever 20, a means 28 for holding the head can also be provided on the lever 21. 51 of brake cable 5 at the level of the retaining chute 20, said holding means 28 being movably mounted between a first position for closing the passage of the head 51 of brake cable 5 and a second erasing position in which the head 51 of brake cable 5 can pass, elastic return means returning said holding means 28 from the erased position to the closed position, so that said holding means 28 exerts a thrust against the head of the brake cable 5. brake cable, which, once the rear end 202 of the retaining chute 2 reached, is held abutting at the rear of said retaining chute 20.

[0068] Preferably this holding means 11 consists of a leaf spring 28 having at least one leaf portion 281 extending substantially parallel to the retaining chute 20 and above it, connected by a bent portion 282 to a blade portion 283 extending across the retaining channel 20 at the rear end 202 thereof and thus closing the passage after said retaining channel 20. The head 51 of the brake cable 5 engaged at the level of the retaining chute 20 against the ramp 232 abuts against the closing portion 283 of the leaf spring 28 (see fig. 5A) and pushes the latter which moves aside and allows said head 51 to pass (see fig. 5B). A blade end portion 284 is provided following the portion shutter 283 after a bent portion 285. Likewise the shutter part 283 has a projection 286 preventing the transverse sliding of the head 51. The head 51 extending beyond the end 202 of the retaining chute 20 is pushed back by force return F of the leaf spring 28 which, at the same time, holds the head 51 against the rear end 202 of the retaining channel 20 and houses the brake cable 5 in the retaining channel 20, cf. fig. 5C.

[0069] The leaf spring 28 is carried by a fixing plate 111 on the lever 21. Thus, the leaf spring 28 has a portion 287 extending parallel to the retaining channel 20 then a bent part 288 in the shape of hairpin to form portion 281.

[0070] Thus, not only is the drum brake according to the invention simple to manufacture but it also offers blind assembly that is easy to implement with simple means.

[0071] Nomenclature

1 drum brake

2 fixed tray

3 first segment

4 second segment

5 brake cable

51 brake cable head

6 wheel cylinder

7 support member called fixed point

8-9 springs

10 hood

11 holding means

111 fixing plate

12 soul

13 sole

14 brake lining

15.16 ends of the soul

17 wear compensation link

18.19 tie rod ends

20 retaining chute

201 front end of retaining chute

202 rear end of retaining chute

21 parking brake actuation lever 22 lever end connection

23 free end of the lever

231 tab of the free end of the lever

232 ramp 24 hole tray

25 support means

26 coil spring

27 support element

271 core of the support element 272 branch of the support element

273, 274 support element retaining tabs

275 support element fixing tab

28 leaf spring

281, 282, 283, 284, 285, 287, 288 blade portions 286 tongue

Claims

[Claim 1] Drum brake (1) comprising a disc-shaped plate (2) having an internal face to which are fixed a wheel cylinder (6) and a support member (7) called fixed point, at diametrically opposite positions, a first and a second segments (3, 4) respectively comprising a core (12) to the outer edge of which is fixed a sole (13) usually called a cylindrically bent sheet metal rim which carries a braking lining ( 14), each core (12) comprising one end resting on a piston of the wheel cylinder (6) and another end resting on the fixed point (7), the drum brake comprising a second actuator comprising a lever (21 ) parking brake which allows the vehicle to be immobilized, this lever (21) being carried by the core (12) of a segment (3, 4), and has one end linked in rotation to a first end of the core (12), and another free end (23) to which is fixed a front end or head of a brake cable (5), which when put in tension, pulls the free end of the lever (21), causing a rotation of the lever (21) in order to move the segments (3, 4) apart, the brake (1) comprising means allowing the blind mounting of said brake cable (5), said means comprising an orifice (24) through made in the plate (2), means for guiding said brake cable (5) consisting of a sheath such as a helical spring (26) extending between the plate orifice (24) and the end free (23) of the lever (21) as well as the support means of said guide means, characterized in that the support means consist of a U-shaped support element (27) of which one of the branches ( 272) extends substantially parallel to the internal face of the plate (2) and the core (271) extends substantially perpendicular to said internal face of the plate (2), the open face of said holding element (27) being oriented towards the center of the plate (2), the sheath (26) being carried in the space defined between the branches of the U.

[Claim 2] Brake (1) according to claim 1, characterized in that the U-shaped support element (27) has a core (271) and a U-shaped branch (272) consisting respectively of a wall and of which the other branch of the U is defined by at least one tongue (273), preferably two, extending from the core (271) of the U-shaped element facing the other branch (272) .

[Claim 3] Brake (1) according to claim 1 or 2, characterized in that the support element (27) has a fixing tongue (275) fixed to the plate (2), preferably on the member of support (7). [Claim 4] Brake (1) according to one of claims 1 to 3, characterized in that sheath (26) has at one end a fixing tip (261) in the orifice (24) of plate (2) and its opposite end (262) is fixed on the end (23) of the lever (21) at the level of the means for fixing the brake cable (5), the trajectory thus defined for the sheath (26) having at the outlet of the orifice (24) of the plate (2) a substantially bent portion causing the sheath (26) to extend along the internal face of the plate (2) to the end (23) of the lever (21).

[Claim 5] Brake (1) according to one of claims 1 to 4, characterized in that the means for fixing the head of the brake cable (5) arranged at the free end (23) of the lever (21) consist of a U-shaped retaining channel (20) for fixing the head (51) of the brake cable (5).

[Claim 6] Brake (1) according to claim 5, characterized in that the retaining chute (20) is made in one piece with the lever (21), the end of the lever (21) being cut so as to present a tongue (231) extending in an axial projection, which is folded so that it defines on one face of this lever (21), that facing the plate (2), the retaining chute (20) of U-shaped cross section whose first free branch is parallel to a second branch constituted by the lever (21).

[Claim 7] Brake (1) according to claim 5, characterized in that the retaining chute

(20) consists of a part with a U-shaped cross section attached to the end (23) of the lever

(21) and fixed thereon.

[Claim 8] Brake (1) according to one of claims 5 to 7, characterized in that the retaining channel (20) has an internal transverse dimension equal to or greater than that of the brake cable (5) and less than the diameter exterior of the head (51) of the cable (5).

[Claim 9] Brake (1) according to one of claims 5 to 8, characterized in that a means (28) for holding the head (51) of the brake cable (5) is provided at the level of the chute retaining means (20), said holding means (28) being movably mounted between a first position for closing the passage of the head (51) of the brake cable (5) and a second clearing position in which the head ( 51) of brake cable (5) can pass, elastic return means bringing said holding means (28) from the erased position towards the closing position, so that said holding means (28) exerts a pushed against the head of the brake cable, which, once the rear end of the retaining channel (20) is reached, is held abutting at the rear of said retaining channel (20). [Claim 10] Brake (1) according to claim 9, characterized in that this holding means (28) consists of a leaf spring having at least one blade portion (281) extending substantially parallel to the chute retaining chute (20) and above it, connected by an elbow portion (282) to a blade portion (283) extending across the retaining chute (20) at the rear end (202 ) of the latter and thus closing the passage after said retaining chute (20), the leaf spring being carried by a fixing plate (29) on the lever (21).

[Claim 11] Brake (1) according to one of claims 5 to 9, characterized in that a cover (10) is fixed on the free end (23) of the lever (21), this cover (10) covering the open part of the retaining chute (20) and comprising at one end an annular-shaped part (101) on which the end (263) of the helical spring (26) is fixed so that the annular part (101) provided of the helical spring (26) is positioned at the level of the brake cable fixing means (5).

[Claim 12] Method of manufacturing a drum brake according to one of claims 2 to 11, characterized in that the sheath (26) is fixed with its ends on the one hand in the orifice (24) of the plate then at the level of the lever (21) and is then slipped into the support element (27) between the branches (272; 273, 274) of said U-shaped support element (27).

[Claim 13] Method of blindly assembling a brake cable on a drum brake according to one of claims 5 to 11, characterized in that the head of the brake cable is engaged from the external face of the plate (2), in an orifice (24) of the plate (2) then this head (51) of brake cable (5) is then guided by guide means such as a helical spring carried by the plate (2) on the side of its internal face, towards the free end (23) of the lever (21) to be fixed there, the head (51) of cable (5) then engaging in the retaining chute (20) arranged at the end of the lever until it is housed after the rear end of said retaining chute (20), the head (51) being retained abutting against said rear end of said retaining chute (20).