INTRINSICALLY DAMPED BRAKE DISC

Abstract: An intrinsically damped brake disc (10) for eliminating braking noise, wherein a weight in the form of a ring (15) or portions of a ring is fixed onto the central element (14) of the disc, a layer of damping material (17) consisting of a metal base and a fibrous covering being interposed between the weight (15) and the central element (11).

Description: This invention relates to an intrinsically damped brake disc, particularly for eliminating braking noise. A brake disc of this kind is known for example from DE-B-16 25 742. The disc brakes of currently produced automobiles, and in particular the front brakes, have a known tendency to produce monochromatic noise in a frequency range of between 1500 and 12000-13000 Hertz. These noises known typically as brake whistle are typically produced at low temperature (80-150°C) and low pressure (5-25 bar), ie during light deceleration braking. This noise has always been a problem in the servicing of a new model, in that even though there are no safety or running comfort implications, the whistle is unpleasant and annoying for the driver and can also lead to false estimation of the state of wear of the brake friction linings. This noise is generally due to the intrinsic vibration frequencies of one or more parts of the braking system. In the known brake disc of DE-B-16 25 742 brake noise is damped by means of a stressed damping device acting between the central element and the braking rim of the disc The object of the present invention is to eliminate braking noise arising from the disc/pad system by damping the intrinsic frequencies of the disc in a more simple and effective way. This object is attained by an intrinsically damped brake disc essentially comprising a central element provided with a sleeve for fixing said disc and a braking rim rigid with said central element, characterised in that a plurality of weights are fixed circumferentially on the surface of said central element in a position opposing said sleeve, a layer of damping material being interposed between said surface and said weights to form a damped resonator. According to the invention said plurality of weights consist of ring sectors. In a further embodiment of this invention said plurality of weights consist of a single ring. Preferably said plurality of weights and said layer of damping material are fixed by screws. Again according to the invention said weights are metal weights. In addition, said weights and said layer of damping material can be fixed by gluing. By way of example said layer of damping material consists of a metal base element and a covering of fibrous material. Again according to the invention said layer of damping material has the same shape as said weights. The invention will be more apparent from the following description with reference to the accompanying drawings in which: Figure 1 is a sectional side view of a disc according to the invention, and Figure 2 is a partial front view of the disc of Figure 1. In the figures the reference numeral 10 indicates overall a disc according to the invention, consisting essentially of a central element 11 comprising a sleeve 12 to which a braking rim 13 is rigidly fixed. On the surface 14 of the central element 11 there is provided a metal ring 15, which is fixed onto it, with a layer of damping material 17 interposed, by a series of screws 16. As an alternative to the single ring weight 15, a plurality of ring sector weights (not shown) can be provided, in which case the layer of damping material will match the shape of the weights. As an alternative to the fixing screws 16, adhesive materials can be used. The structural simplicity of the present invention means that it can be used for the simple and low-cost construction of a system equivalent to a damped resonator.

Claims: An intrinsically damped brake disc (10) essentially comprising a central element (11) provided with a sleeve (12) for fixing said disc (10) and a braking rim (13) rigid with said central element (11), characterised in that a plurality of weights are fixed circumferentially on the surface (14) of said central element (11) in a position opposing said sleeve (12), a layer of damping material (17) being interposed between said surface (14) and said weights to form a damped resonator. A brake disc as claimed in claim 1, characterised in that said plurality of weights consist of ring sectors. A brake disc as claimed in claim 1, characterised in that said plurality of weights consist of a single ring (15). A brake disc as claimed in claim 1, characterised in that said plurality of weights and said layer of damping material (17) are fixed by screws (16). A brake disc as claimed in claim 1, characterised in that said weights are metal weights. A brake disc as claimed in claim 1, characterised in that said weights and said layer of damping material (17) can be fixed by gluing. A brake disc as claimed in claim 1, characterised in that said layer of damping material (17) consists of a metal base element and a covering of fibrous material. A brake disc as claimed in claim 1, characterised in that said layer of damping material (17) has the same shape as said weights.

Inventors: DALCO', CLAUDIO, PONCINI, GIANFRANCO
Applicants: FIAT AUTO S.P.A.
Application year: 1991
Main classification: F16D65
IPC codes: F16D65