FR3008460A1 - CROSS-TYPE CHASSIS ELEMENT AND DRUM BRAKE COMPRISING SUCH A TRAVERSE - Google Patents

Abstract

The invention relates to a chassis member of cross-type and drum brake comprising or cooperating with such a cross member. The subject of the invention is a vehicle chassis element (39) comprising assembly means with at least one wheel pivot and means (50) for securing with a drum brake (10 '), characterized in that it further comprises support means (24, 38) on at least one of the two ends (22, 26) of at least one brake segment (18). The present invention applies to the automotive industry.

Description

The invention relates to a chassis member of cross-type and drum brake comprising or cooperating with such a cross member. It is known to produce drum brakes comprising a drum connected in rotation to the wheel of a motor vehicle and a stator comprising a plate bearing functional elements of the brake and in particular: two segments carrying the friction lining a wheel cylinder application of force on a first end of said segments a bearing abutment, called "fixed point", a second end of each of said segments. As a result, the plate must support and transmit the forces necessary for the application of the friction linings on the drum and therefore it must have a thickness and a large mass.

But the mass of a brake is not suspended and influences the dynamic behavior of a vehicle. In addition the fuel consumption of a motor vehicle is an increasing function of the mass of the vehicle. It is therefore an object of the present invention to provide an element of the vehicle chassis such as a cross member and / or an associated drum brake having a reduced mass while ensuring, on command, the desired braking of the vehicle. These objects are achieved by a frame member, in particular a cross member and / or a drum brake according to the invention, the crossmember having means for absorbing forces that can be exerted on the ends of the segments. The subject of the invention is mainly a vehicle chassis element comprising assembly means with at least one wheel pivot and means for securing with a drum brake, characterized in that it also comprises support means on at least one of the two ends of at least one brake segment.

The invention also relates to a chassis member according to the invention characterized in that said element is a cross member capable of carrying the rear wheels of a motor vehicle. The invention also relates to a chassis element according to the invention, characterized in that said support means comprise a fixed point for receiving a first end of a brake segment. The invention also relates to a chassis member according to the invention characterized in that said support means comprise a wheel cylinder for receiving a second end of a brake shoe. The invention also relates to a drum brake adapted to cooperate with a chassis member according to the invention, characterized in that it comprises a plate, at least one brake segment means comprising at least one end characterized in that means for receiving a support means secured to a chassis member of a vehicle in a condition in which said end of said brake shoe is disposed opposite said support means. The invention also relates to a drum brake according to the invention characterized in that said means for receiving a support means comprise a passage opening of a fixed point. The invention also relates to a drum brake according to the invention characterized in that said means for receiving a support means comprise a passage opening of a wheel cylinder. The invention also relates to a brake according to the invention characterized in that the fixed point forming said support means comprises a tongue having transverse edges disposed vis-à-vis said first ends of brake segments.

The invention also relates to a brake according to the invention characterized in that it comprises a plate made of sheet steel whose thickness is less than or equal to 2 mm. The invention also relates to a brake according to the invention characterized in that it comprises a plate of composite material.

Other features and advantages will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is a front view which represents a drum brake of the type known; - Figure 2 is a sectional view of Figure 1 according to a vertical axial section plane; FIG. 3 is a front view showing a first variant embodiment of a drum brake according to the invention; - Figure 4 is a sectional view along a vertical plane of the drum brake of Figure 3; - Figure 5 is a front view of a cross member according to the invention intended to be assembled with the drum brake of Figures 3 and 4; FIG. 6 is a front view showing a second variant embodiment of a drum brake according to the invention; - Figure 7 is a sectional view along a vertical plane of the drum brake of Figure 6; - Figure 8 is a front view of a cross member according to the invention intended to be assembled with the drum brake of Figures 6 and 7; - Figure 9 is a sectional view along a vertical plane of the drum brake of Figure 9; In Figures 1 to 9 we used the same references to designate the same elements. For the remainder of the description, orientations will be adopted: - longitudinal directed from back to front and indicated by the arrow "L" of the figures; - vertically directed from bottom to top and indicated by the arrow "V" in the figures; - transverse directed from left to right and indicated by the arrow "T" of the figures.

These orientations are adopted in a nonlimiting manner only to simplify the understanding of the description. The vertical direction is in particular a purely geometrical indication unrelated to the direction of gravity. The longitudinal direction "L" being parallel to an axis "A" of the drum, it will also be called "axial" direction in the description.

A plane orthogonal to this longitudinal direction will be called "radial". FIGS. 1 and 2 show a motor vehicle drum brake 10 which is intended to be mounted on a wheel (not shown) rotatably mounted about a longitudinal axis "A" of rotation. The brake 10 comprises a plate 12 which is fixedly mounted relative to the chassis of the motor vehicle including a cross member connecting the rear wheels of the vehicle. The plate 12 extends in a plane generally transverse to the axis "A" of the wheel. The brake 10 also comprises a drum 14 which is capable of carrying a wheel (not shown) associated. The drum 14 has a cylindrical friction skirt 16, which has also been shown in dashed lines in FIG. 1, which extends longitudinally forwards from a front face 34 of the plate 12 and is mounted coaxially with the 'A' axis of the wheel. The drum 14 is thus rotatably mounted relative to the plate 12. Two braking segments 18 are mounted on the plate 12. The two segments 18 here have a structure and an arrangement that are identical by symmetry with respect to a vertical axis passing through the axis "A" rotation. Only one of the two segments 18 will therefore be described later. The segment 18 extends generally vertically inside the drum 14. The segment 18 has a curvature centered on the axis "A" of rotation, which corresponds to that of the skirt 16. The segment 18 has a face 20 of external friction which is turned towards an inner face of friction of the skirt 16. The friction face 20 thus also has a curvature corresponding to that of the inner skirt 16 of friction of the drum 14.

The segment 18 is mounted substantially pivotally on the plate 12 by a first end 22, below, about a fixed point defining a longitudinal axis "B" pivoting between: - an inactive position in which it is elastically biased towards the axis "A" of the drum 14 with a radial clearance determined with respect to the skirt 16 friction, and - an active position in which the friction face 20 is biased radially against the inner face of the skirt 16 of friction. The fixed point is made in relief, longitudinally, by stamping the plate 12 with, optionally, the joining of an insert. The stamping operation requires a thick plate, its thickness must be further increased to support the forces exerted on the fixed point and on a receiving opening of the wheel cylinder 24.

The elastic return of the segments 18 to their inactive position is achieved by means of a spring 23 which is stretched transversely between the two first, lower, ends 22 of the segments 18. To push the two segments 18 towards their active position against of the elastic return force, a cylinder 24 of hydraulic wheel 15 is interposed transversely between second ends 26, upper, opposite said first ends 22, lower segments 18. The wheel cylinder 24 comprises two opposed pistons 28 which are slidably mounted transversely in a hydraulic chamber of a body. Each piston 28 bears on the second upper end 26 of the associated segment 18. Each piston 28 is thus capable of biasing the associated braking segment 18 towards its active position as soon as the fluid pressure increases in the hydraulic chamber of the cylinder 24. The Applicant has discovered that the forces exerted on the plate 12 by the point fixed and / or the wheel cylinder 24 are compression forces exerted in the plane of the plate 12 (plane parallel to the plane (V, T)). However, the drum brake is fixed on an element 39 of the vehicle frame, typically a cross member of the wheel pivot whose intrinsic rigidity is sufficient for this effort recovery. FIGS. 3 and 4 show the preferred embodiment of the drum brake according to the invention comprising a plate 12 provided with an opening 36 for passing through a fixed point 38 secured to and / or integrated with an element of the invention. chassis of the vehicle, preferably to the cross member 39 connecting the wheels (preferably the rear wheels). The fixed point 38 is advantageously formed by a tongue of the crosspiece folded longitudinally, the first ends 22, lower, segments 18 bearing on the transverse edges 40 of the tongue. Alternatively, not shown, the fixed point 38 has a U-shape or forms a rectangular parallelepiped secured to the cross member 39. The cross member 39 has a fixed point at each of its ends respectively corresponding to the left wheel and the right wheel. However only one end of the cross member 39 is illustrated in the figures.

The brake 10 'according to the invention advantageously comprises all or part of the known devices in the field of the drum brake such as a parking brake lever 42 provided with a cable hooking device 44 (not shown), a wear compensation device 46 called RAI and / or fixing holes 48 which can be arranged opposite the holes 50 for fastening the crossmember 39 for assembly, for example by bolts / nuts . Figures 6 and 7 can be seen a brake 10 'according to the invention provided with a fixed point 38 reported provided with a longitudinal protrusion 20 front including the tangential faces 40 for receiving the first ends 22, lower segments 18 are advantageously adapted to the shape of said ends to ensure precise guiding and positioning when the force is taken up by the fixed point 38. In the example advantageously illustrated, the protuberance before 25 has a cross-section (in the plane (V , T)) a rhombus shape with rounded corners. Advantageously, each transverse edge 40 of the fixed point 38 has a recess 52 (or on the contrary a protuberance) complementary to the shape of the first, lower end 22 of the segments 18. Advantageously, the fixed point 38 comprises a rear longitudinal tail 54 of fastener, threaded receiving a fixing nut 56. Advantageously a seal (not shown) is interposed between the fixed point 38 and the opening 36.

In FIG. 9, a brake 10 'can be seen according to the invention, the plate 12 includes a second opening 36' allowing the passage of a wheel cylinder 24 secured to an element of the chassis (with the cross member 39 in the illustrated advantageous example). Advantageously a seal (not shown) is disposed at the openings 36 and / or 36 '. It is understood that a brake whose wheel cylinder 24 is carried by a frame member (preferably a cross member 39) but whose fixed point 38 is carried by the plate 12 does not depart from the scope of the present invention. By releasing the plate 12 of the brake 10 'according to the invention and moreover, without requiring deep drawing, the designer of the tray 12 is left with great freedom in the choice of geometries and / or material. For example, for a brake having a diameter of 228.6 mm (9 "), a plate 12 made of sheet steel is used whose thickness is chosen between 2 mm and 0.5 mm, preferably between 1.5 mm. and 0.8 mm, for example equal to 1.2; 1 or 0.9 mm. As a variant is implemented a plate of composite material, plastic material advantageously loaded and / or reinforced with fibers. a platen 12 having an inner and / or outer layer of vibration-absorbing material such as elastomer The present invention is applicable to the automotive industry References 10 brake 10 'brake according to the invention 12 plate 14 drum 16 skirt 18 segments 20 friction face of the segment 22 first lower end of the segment 23 spring 24 wheel cylinder 26 second upper end of the segment 28 piston of the wheel cylinder 32 attachment face of the wheel cylinder 34 front face of the plate 36, 36 'opening 38 fixed point 39 cross 40 transver edges seals 42 lever 44 rope clamp 46 wear compensation device 48 holes 50 holes 52 guide recess 54 tail 56 nut15

Claims (10)

REVENDICATIONS1. Vehicle chassis element (39) comprising assembly means with at least one wheel pivot and means (50) for securing with a drum brake (10 '), characterized in that it further comprises means for support (24,38) on at least one of the two ends (22,26) of at least one brake segment (18). 2. Frame element according to claim 1 characterized in that said element is a cross member capable of carrying the rear wheels of a motor vehicle. 3. Chassis element according to any one of the preceding claims characterized in that said support means comprise a fixed point (38) for receiving a first end (22) of a segment (18) brake. 4. Frame element according to any one of the preceding claims characterized in that said support means comprise a wheel cylinder (24) for receiving a second end (26) of a segment (18) brake. 5. Drum brake adapted to cooperate with a frame member according to any preceding claim characterized in that it comprises a plate (12), at least one segment (18) brake means comprising at least one end (22, 26) characterized in that means (36, 36 ') for receiving a support means (24, 38) secured to a chassis member (39) of a vehicle in a condition in which said end (22, 26) of said brake shoe (18) is disposed opposite said bearing means (24, 38). 6. Drum brake according to claim 5 characterized in that said means (36,36 ') for receiving a support means (24,38) comprise an opening (36) for passage of a fixed point (38). ). 7. Drum brake according to claim 5 or 6 characterized in that said means (36,36 ') for receiving a support means (24,38) comprise an opening (36') for the passage of a cylinder wheel (24). 8. Brake according to claim 6 or 7 characterized in that the fixed point (38) forming said support means comprises a tabuettant having transverse edges (40) disposed vis-à-vis said first ends (22) of segments ( 18) brakes. 9. Brake according to any one of claims 5 to 8 characterized in that it comprises a plate (12) made of steel sheet whose thickness is less than or equal to 2 mm. 10. Brake according to any one of the preceding claims characterized in that it comprises a plate (12) of composite material.