Drum brake assembly for vehicle

Abstract

This vehicle braking assembly (1) comprises a brake drum (2) intended to be integral with a wheel of the vehicle and having an outer cylindrical surface (6) and a braking track (8) formed by an inner cylindrical surface (7) opposite the outer cylindrical surface (6), and a brake backing plate (3) comprising an outer radial end portion (11) oriented substantially radially and disposed opposite said brake drum (2) on an inner side of the vehicle. The outer cylindrical surface (6) extends towards the inner side of the vehicle so as to cover an outer radial end face (12) of the outer radial end portion (11) of the brake backing plate (3). (See Figure 1 for abbreviations)

Description

Title of the invention: Drum brake assembly for vehicle technical field

[0001] The invention relates to a drum braking assembly for a motor vehicle. Prior art

[0002] Generally, motor vehicles include a braking system which includes a brake pedal acting on a master cylinder to transmit, via hydraulic circuits, fluid pressure to braking devices which act on each wheel of the vehicle.

[0003] A braking device, known per se and widely used, comprises a drum of brake comprising an inner cylindrical surface called brake track, which is intended to receive the pressure of two brake segments which move apart from each other under the effect of a hydraulic control cylinder.

[0004] In the context of brake drum development, it is advantageous to increase the radial dimension of the brake track. Indeed, a larger radial brake track offers a greater contact area with the brake shoes. This results in improved braking performance and heat dissipation during braking, along with increased durability.

[0005] However, the drum must have a minimum thickness sufficient for good resistance to thermomechanical stresses. Indeed, by increasing the radial dimension of the braking track, it is necessary, for a given drum thickness, to increase the drum's outer diameter.

[0006] On the other hand, the external diameter of the drum must not exceed a maximum permissible dimension under penalty of incompatibility with the existing production equipment.

[0007] Furthermore, to protect the inside of the brake drum, a brake plate is conventionally used, positioned opposite the brake drum to create baffles that make it difficult for water or dust to enter the inside of the brake drum. Generally, to ensure adequate protection, the radial end of the brake plate extends to almost the outer diameter of the drum.

[0008] It is therefore understood that increasing the radial dimension of a conventional braking track requires a joint modification of the drum and the brake plate so as to be able to simultaneously comply with the aforementioned constraints of minimum thickness, maximum outside diameter and protection against water and dust. Description of the invention

[0009] In view of the foregoing, the invention aims to provide a drum braking assembly for a vehicle protected against the intrusion of water or dust and which has a large braking track and an outside diameter which does not exceed a maximum permissible diameter.

[0010] The invention relates to a vehicle braking assembly comprising a brake drum intended to be fixed to a wheel of the vehicle and having an outer cylindrical surface and a braking track formed by an inner cylindrical surface opposite the outer cylindrical surface, and a brake backing plate comprising an outer radial end portion oriented substantially radially and disposed opposite the brake drum on an inner side of the vehicle. The outer cylindrical surface extends towards the inner side of the vehicle so as to cover an outer radial end face of the outer radial end portion of the brake backing plate. This feature provides protection against the intrusion of water or dust.

[0011] According to one feature, the outer cylindrical surface completely covers the outer radial end face of the outer radial end portion of the brake plate. This feature further improves protection against the intrusion of water or dust.

[0012] Advantageously, the brake plate is provided with a tab comprising a fixing portion rigidly attached to the outer radial end portion and a cantilevered portion extending axially into a receiving chamber formed from a lateral surface of the brake drum. Such a configuration further improves protection against the intrusion of water or dust.

[0013] Preferably, the tongue includes a rim extending radially towards the outer cylindrical surface of the brake drum.

[0014] According to another feature, the cantilevered portion extends radially into the receiving chamber. This feature facilitates the drainage of infiltrating water.

[0015] Advantageously, the receiving chamber is provided with an internal groove to form a drip edge. The presence of such a groove prevents the runoff of infiltrating water into the interior of the braking assembly.

[0016] According to another feature, the inner groove is arranged between the outer cylindrical surface of the brake drum and the tab of the brake plate.

[0017] For example, the brake drum has an outside diameter less than or equal to 300 mm.

[0018] For example, the braking track has a diameter approximately equal to 254 mm.

[0019] According to another aspect, the invention relates to a vehicle equipped with at least one braking system as defined above. Brief description of the drawings

[0020] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0021] [Fig-1] is a partial axial cross-sectional view of a braking assembly according to a example of an implementation of the invention; and

[0022] [Fig.2] is a detailed view of an interface between a drum and a brake plate of the braking assembly of [Fig.1]. Detailed description of at least one embodiment

[0023] Figure 1 shows, in axial section, a portion of a vehicle braking assembly 1 according to an embodiment of the invention. The braking assembly 1 comprises a brake drum 2 attached to a wheel (not shown) of the vehicle and associated with a brake plate 3. The brake drum 2 comprises an outer radial end 4 and an inner radial end 5.

[0024] The brake drum 2 is provided at its outer radial end 4, with an outer cylindrical surface 6.

[0025] The brake drum 2 is provided at its inner radial end 5, with an inner cylindrical surface 7 opposite the outer cylindrical surface 6. The inner cylindrical surfaces 7 and outer cylindrical surfaces 6 define the axial thickness of the brake drum 2.

[0026] The inner cylindrical surface 7 forms a braking track 8 intended to receive the pressure of two brake segments 9 which move apart from each other under the effect, for example, of a mechatronic actuator 10. It remains of course possible to provide other types of actuators known and compatible with the intended application.

[0027] The brake plate 3 is arranged opposite the brake drum 2 on an inner side of the vehicle and is fixed to an axle (not shown) carrying the wheel of the vehicle.

[0028] The brake plate 3 includes an external radial end portion 11 which is substantially radially oriented.

[0029] Advantageously, the outer cylindrical surface 6 extends towards the inner side of the vehicle so as to cover an outer radial end face 12 of the end portion 11. Preferably, the outer cylindrical surface 6 completely covers the face 12. Alternatively, it is possible for the outer cylindrical surface 6 to only partially cover the face 12.

[0030] Fig. 2 is a detailed view of the interface between the plate 3 and the drum 2 of Fig. 1. It should be noted that identical or similar elements bear the same reference numerals from one figure to another.

[0031] The brake plate 3 is provided with a tab 13 comprising a fixing portion 13a and a cantilever portion 13b. The fixing portion 13a is rigidly fixed to the outer radial end portion 11. The fixing of the fixing portion 13a to the outer radial end portion 11 is achieved by any known and compatible rigid fastening method, for example, welding or screwing.

[0032] The tongue 13 is disposed on an external side of the vehicle relative to the external radial end portion 11. The cantilevered portion 13b extends axially into a receiving chamber 14 formed from a lateral surface 15 of the brake drum 2.

[0033] Advantageously, the tongue 13 includes at a free end a rim 13c extending radially towards the outer cylindrical surface 6 of the brake drum 2.

[0034] According to an embodiment not illustrated, the cantilevered part 13b extends both axially and radially into the receiving chamber 14.

[0035] As illustrated in [Fig. 2], the receiving chamber 14 is provided with an internal groove 16 to form a drip edge. The internal groove 16 is located between the outer cylindrical surface 6 of the brake drum 2 and the tab 13 of the brake plate 3. The internal groove 16 is here semi-circular in shape. Alternatively, it is possible to provide a different shape for the internal groove 16, for example, an elliptical, triangular, or rectangular shape.

[0036] Preferably, the brake drum 2 has an outside diameter less than or equal to 300 mm within manufacturing tolerances and the brake track 8 has a diameter substantially equal to 254 mm.

Claims

Demands

1. Vehicle braking assembly (1) comprising a brake drum (2) intended to be integral with a wheel of the vehicle and having an outer cylindrical surface (6) and a braking track (8) formed by an inner cylindrical surface (7) opposite the outer cylindrical surface (6), and a brake plate (3) comprising an outer radial end portion (11) oriented substantially radially and disposed opposite said brake drum (2) on an inner side of the vehicle, characterized in that the outer cylindrical surface (6) extends towards the inner side of the vehicle so as to cover an outer radial end face (12) of the outer radial end portion (11) of the brake plate (3).

2. Braking assembly (1) according to claim 1, wherein the outer cylindrical surface (6) fully covers the outer radial end face (12) of the outer radial end portion (11) of the brake plate (3).

3. Braking assembly (1) according to claim 1 or 2, wherein the brake plate (3) is provided with a tongue (13) comprising a fixing part (13a) rigidly fixed on the outer radial end portion (11) and a cantilever part (13b) extending axially into a receiving chamber (14) formed from a lateral surface (15) of the brake drum (2).

4. Braking assembly (1) according to claim 3, wherein the tongue (13) includes a rim (13c) extending radially towards the outer cylindrical surface (6) of the brake drum (2).

5. Braking assembly (1) according to claim 3 or 4, wherein the cantilevered part (13b) extends radially into the receiving chamber (14).

6. Braking assembly (1) according to any one of claims 3 to 5, wherein the receiving chamber (14) is provided with an internal groove (16) so as to form a drip edge.

7. Braking assembly (1) according to claim 6, wherein the inner groove (16) is disposed between the outer cylindrical surface (6) of the brake drum (2) and the tongue (13) of the brake plate (3).

8.

9.

10. Braking assembly (1) according to any one of claims 1 to 7, wherein the brake drum (2) has an outside diameter less than or equal to 300 mm. Braking assembly (1) according to any one of claims 1 to 8, wherein the braking track (8) has a diameter substantially equal to 254 mm. Vehicle equipped with at least one braking system (1) according to any one of claims 1 to 9.

Images