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) disposed opposite said brake drum (2) on an inner side of the vehicle and comprising an outer radial end portion (10) of the backing plate (3) extending substantially axially into a receiving chamber (11) formed from a lateral surface (12) of the brake drum (2) disposed between the outer and inner cylindrical surfaces (6, 7). The receiving chamber (11) is provided with means (13) for trapping foreign substances capable of entering the braking assembly (1). Figure for the abbreviation: [Fig 1]

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 provides 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 integral with a wheel of the vehicle and provided with an outer cylindrical surface and a braking track formed by an inner cylindrical surface opposite the outer cylindrical surface, and a brake plate disposed opposite the brake drum on an inner side of the vehicle and comprising an outer radial end portion of the plate extending substantially axially into a receiving chamber formed from a lateral surface of the brake drum disposed between the outer and inner cylindrical surfaces.

[0011] The receiving chamber is equipped with means for trapping foreign substances that could enter the braking assembly. Such a braking assembly is protected against foreign substances that could infiltrate it and complies with the minimum thickness and maximum outside diameter requirements.

[0012] According to one feature, the trapping means include an internal groove.

[0013] Advantageously, the inner groove is arranged as an extension of a face radial shape of the receiving chamber. This feature promotes good collection of infiltrating water.

[0014] Preferably, the inner groove is formed from an inner axial face of the receiving chamber.

[0015] For example, the inner groove includes at least one connecting fillet.

[0016] According to another feature, the trapping means include a rim positioned on the inner axial face of the receiving chamber.

[0017] For example, 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 substantially radially opposite the lateral surface of the brake drum. This configuration improves protection against the intrusion of foreign substances.

[0018] For example, the brake drum has an outside diameter less than or equal to 300 mm.

[0019] For example, the braking track has a diameter approximately equal to 254 mm.

[0020] 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

[0021] 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 drawing in which:

[0022] [Fig-1] is a partial axial cross-sectional view of a braking assembly according to a example of an implementation of the invention. Detailed description of at least one embodiment

[0023] The accompanying single figure 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 integral with a wheel (not shown) of the vehicle and an associated brake backing 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 of an actuator (not shown).

[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 10 which extends substantially axially into a receiving chamber 11 formed from a lateral surface 12 of the brake drum 2 disposed between the external and internal cylindrical surfaces 6, 7.

[0029] The receiving chamber 11 is equipped with means for trapping foreign substances 13 that may enter the braking assembly 1.

[0030] As illustrated in the figure, the trapping means include for example an internal groove 14 formed from an internal axial face 15 of the receiving chamber 11.

[0031] Preferably, the inner groove 14 is arranged as an extension of a radial face 16 of the receiving chamber 11.

[0032] According to the embodiment illustrated in the figure, the inner groove 14 includes at least one fillet 14a, here a fillet connecting to the radial face 16. Alternatively, it is possible to provide an inner groove 14 with a fillet connecting to the inner axial face 15, or even an inner groove 14 without a fillet connecting. In the latter case, the section of the inner groove 14 can for example have a triangular, rectangular or trapezoidal shape.

[0033] For example, the trapping means 13 include a rim 17 disposed on the inner axial face 15 of the receiving chamber 11. The rim 17 may be an added part rigidly fixed to the outer radial end portion 11 by any known and compatible means. Alternatively, the rim 17 may be made by machining an adjacent portion of the inner axial face 15 of the receiving chamber 11. In this case, the rim 17 and the brake drum 2 form a single piece.

[0034] In the example illustrated in the accompanying figure, the brake plate 3 is provided with a tab 18 comprising a fixing portion 18a and a cantilever portion 18b. The fixing portion 18a is rigidly fixed to the outer radial end portion 10. The fixing of the fixing portion 18a to the outer radial end portion 10 is achieved by any known and compatible rigid fastening method, for example, welding or screwing.

[0035] Preferably, the tab 18 is disposed on an external side of the vehicle relative to the external radial end portion 10. The bracket portion 18b extends substantially radially in relation to the lateral surface 12 of the brake drum 2.

[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) disposed opposite said brake drum (2) on an inner side of the vehicle and comprising an outer radial end portion (10) of the plate (3) extending substantially axially into a receiving chamber (11) formed from a lateral surface (12) of the brake drum (2) disposed between the outer and inner cylindrical surfaces (6, 7), characterized in that the receiving chamber (11) is provided with means for trapping foreign substances (13) capable of entering the braking assembly (1).

2. Braking assembly (1) according to claim 1, wherein the trapping means (13) comprise an internal groove (14).

3. Braking assembly (1) according to claim 2, in which the inner groove (14) is arranged as an extension of a radial face (16) of the receiving chamber (11).

4. Braking assembly (1) according to claim 2 or 3, wherein the inner groove (14) is formed from an inner axial face (15) of the receiving chamber (11).

5. Braking assembly (1) according to any one of claims 2 to 4, wherein the inner groove (14) includes at least one connecting fillet (14a).

6. Braking assembly (1) according to claim 1, wherein the trapping means (13) comprise a rim (17) disposed on an inner axial face (15) of the receiving chamber (11).

7. Braking assembly (1) according to any one of claims 1 to 6, wherein the brake plate (3) is provided with a tab (18) comprising a fixing part (18a) rigidly fixed on the outer radial end portion (10) and a cantilever part (18b) extending substantially radially opposite the lateral surface (12) of the brake drum (2).

8. 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.

9. 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.

10. Vehicle equipped with at least one braking system (1) according to any one of claims 1 to 9.

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