Disc brakes for vehicles

Abstract

Disc brake for vehicles comprising: a disc (10) which is rotated together with a wheel of a vehicle; a pair of brake pads (11, 12) which are arranged opposite each other on both sides of the disc (10); and a pair of wedge elements (30, 40) which are mounted on the rear sides of the brake pads (11, 12), wherein the upper ends of the brake pads (11, 12) are each pivotably attached to the wedge elements (30, 40) and the lower ends of the brake pads (11, 12) are supported by elastic elements (15) such that they project towards the disc (10).

Description

The present application claims the benefits of Korean patent application No. 1020090060060, filed on July 2, 2009 with the Korean Patent Office, the disclosure of which is hereby incorporated in its entirety into the present application by reference. BACKGROUND 1. Field of the invention Exemplary embodiments of the present invention relate to a disc brake for vehicles in which brake pads are pressed against a disc by wedge elements. 2. Description of the state of the art In general, a disc brake is a device that achieves braking force by applying pressure to the outer surface of a disc, which is rotated along with a wheel, using brake pads. Among disc brakes, there is the electronic wedge brake (EWB; Electro Wedge Brake), in which brake pads are pressed against a disc using wedge elements that slide along an inclined plane. In such an EWB, for example, the wedge elements are pushed along inclined planes by a drive mechanism, thus pressing the brake pads against the disc. An EWB for vehicles comprises an output motor for actuating the wedge elements, a screw shaft connected to a rotary shaft of the drive motor, wherein the wedge elements are connected to the screw shaft in such a way that they move forward and backward in a direction parallel to the disc by actuation of the drive motor, and a brake caliper housing provided with wedge sections formed in a shape corresponding to the wedge elements in order to press the wedge elements against the disc. In the EWB, when the drive motor is actuated to move the wedge elements in one direction, the brake pads touch the disc, and at the same time the wedge elements are pushed along inclined planes of the wedge sections to press the brake pads more firmly against the disc, thus carrying out the braking process. In the case of such a conventional EWB for vehicles, however, it can happen that if adhesion occurs between the disc and the wedge elements as a result of moisture or other foreign bodies or foreign substances, provided that sufficient clearances between the disc and the wedge elements are not achieved as a result of vibration generated while driving a vehicle, the brake pads are tightened in the direction of rotation of the disc according to the rotation of the disc, and this can result in an unintended braking process. EP 0 141 409 A1 describes a mechanism for actuating disc brakes in motor vehicles. The mechanism comprises a box-like body that is fixedly attached to the brake caliper of the disc brake and slidably accommodates a push rod that is movable parallel to the axis of the brake disc; wherein the push rod comprises at least one ramped section that engages in a first wedge having an inclined surface that slidably engages with an inclined surface of a self-adjusting wedge, which, on its opposite side relative to the first wedge, engages with a piston that acts on the friction lining to force it into engagement with the brake disc. KR 10 2003 0 034 883 A describes an arrangement for a disc brake to prevent uneven wear of brake pads, wherein at least one spring is arranged between a first base plate and a second base plate which carries a brake pad. SUMMARY OF THE INVENTION Therefore, an aspect of the present invention is to provide a disc brake for vehicles that prevents the generation of a braking force in an unintended state. Additional aspects of the invention are partly set out in the following description and partly become apparent from the description or can be learned by practicing the invention. In accordance with one aspect of the present invention, a disc brake for vehicles comprises a disc which is rotated together with a wheel of a vehicle, a pair of brake pads which are arranged opposite each other on both sides of the disc, and a pair of wedge elements which are mounted on the rear sides or rear surfaces of the brake pads, wherein the upper ends of the brake pads are pivotably connected to the wedge elements and the lower ends of the brake pads are supported by elastic elements such that they project towards the disc. The disc brake for vehicles may further comprise a pair of base plates which are attached to the backs of the brake pads, and the upper ends of the base plates may each be pivotably attached to the wedge elements, and thus the brake pads may each be pivotably or rotatably connected to the wedge elements by the base plates. Protruding joint or hinge parts, i.e., joint or hinge projections for pivoting or rotating the base plates on the wedge elements, can be arranged so that they protrude from both sides of the upper ends of the base plates, and joint or hinge sections on which the joint or hinge projections are rotatably or pivotably mounted can be formed on the wedge elements. Receptacles for receiving the elastic elements can be provided as recesses on the wedge elements. BRIEF DESCRIPTION OF THE DRAWINGS These and / or further aspects of the invention will become apparent and better understood from the following description of the exemplary embodiments, which is given in conjunction with the accompanying drawings, wherein: Fig. 1 is a perspective exploded view schematically illustrating a disc brake for vehicles in accordance with an exemplary embodiment of the present invention; and Fig. 2 and Fig. 3 are longitudinal sectional views illustrating the operation of the disc brake for vehicles in accordance with the exemplary embodiment of the present invention. DETAILED DESCRIPTION Detailed reference will now be made to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, whereby identical reference numerals consistently refer to identical elements. As shown in Fig. 1 and Fig. 2, a disc brake for vehicles in accordance with an embodiment of the present invention comprises a disc 10 which is rotated together with a wheel (not shown) of a vehicle, a pair of brake pads 11 and 12 which are arranged on both sides of the disc 10 in order to brake the disc 10, a brake caliper housing 20 and a pair of wedge elements 30 and 40 in order to press the two brake pads 11 and 12 against the disc 10, and a drive device 60 for actuating the pair of wedge elements 30 and 40 such that they exert pressure on the two brake pads 11 and 12. The two brake pads 11 and 12 comprise an inner brake pad 11, which rubs against the inside of the disc 10, and an outer brake pad 12, which rubs against the outside of the disc 10. The two brake pads 11 and 12 are supported by a carrier 50, which is attached to a joint section (not shown) of the vehicle, in such a way that they can move forwards and backwards relative to the disc 10, thus enabling them to press against both surfaces or sides of the disc 10. The brake caliper housing 20 is connected to guide rods 21, which are attached to both sides of the carrier 50 via guide holes provided on both sides, in such a way that the brake caliper housing 20 can move forwards and backwards.When the inner brake pad 11 rubs against the inner surface of the disc 10, the brake caliper housing 20 moves backwards from the disc 10 and exerts pressure on the outer surface of the outer brake pad 12, causing the outer brake pad 12 to rub against the outer surface of the disc 10. The pair of wedge elements 30 and 40 comprises an inner wedge element 30, mounted on the rear side of the inner brake pad 11, and an outer wedge element 40, mounted on the rear side of the outer brake pad 12. An inner wedge section 22 and an outer wedge section 23, facing each other, are provided on both inner side walls of the brake caliper housing 20 such that they face inclined planes of the two wedge elements 30 and 40. That is, the inner brake pad 11 and the outer brake pad 12 are arranged opposite each other in the brake caliper housing 20, with the inner brake pad 11 and the outer brake pad 12 each mounted on the inner wedge element 30 and the outer wedge element 40, respectively, and the disc 10 positioned between the inner brake pad 11 and the outer brake pad 12. Inclined planes 30a, 30b and 40a, 40b, which are bilaterally symmetrical to form V-shaped valleys, are provided on the rear faces of the two wedge elements 30 and 40, which are provided with the front faces on which the brake linings 11 and 12 are mounted, and the inner wedge section 22 and the outer wedge section 23 are provided with inclined planes 22a, 22b and 23a, 23b, which form V-shaped mountains, opposite the inclined planes 30a, 30b and 40a, 40b of the two wedge elements 30 and 40. The inner wedge element 30 and the outer wedge element 40 comprise a first guide rod 31 and a second guide rod 41, which are positioned so that they project opposite each other and are mounted to allow movement forwards and backwards relative to the disk 10. In this embodiment, a guide hole 31a, into which the second guide rod 41 is movably inserted, is formed by the first guide rod 31, and thus the inner wedge element 30 and the outer wedge element 40 are mounted to allow movement forwards and backwards through the first guide rod 31 and the second guide rod 41. The drive device 60 is mounted on the outer surface of the inner wedge section 22. The drive device 60 comprises a drive motor 61, which is provided with a rotating shaft 61a extending through the inner wedge section 22 in a pressure-exerting direction towards the inner brake lining 11; a screw shaft 62, which meets the rotating shaft 61a of the drive motor 61 at a right angle and is arranged parallel to the disc 10; a worm 63, which is mounted at the front end of the rotating shaft 61a; and a worm wheel 64, which is mounted in the center of the screw shaft 62 so that it can be connected to the worm 63. Guide sections 32, to which the screw shaft 62 is bolted, are formed on the inner wedge element 30 such that the inner wedge element 30 can move by receiving a driving force transmitted through the screw shaft 62. In order to minimize friction between the disc 10 and the brake pads 11 and 12, even if friction occurs between the disc 10 and the brake pads 11 and 12 under the condition that no braking operation is carried out, the upper ends of the two brake pads 11 and 12 are pivotably or rotatably mounted on the wedge elements 30 and 40, and the lower ends of the two brake pads 11 and 12 are elastically supported by elastic or spring elements 15 so that they protrude towards the disc 10. In this embodiment, the base plates 13 and 14, to which the two brake linings 11 and 12 are attached, are each arranged on the rear sides of the two brake linings 11 and 12, and the upper ends of the two base plates 13 and 14 are pivotably mounted on the wedge elements 30 and 40, and thus the brake linings 11 and 12 are pivotably or rotatably mounted on the wedge elements 30 and 40 by means of the base plates 13 and 14. Protruding joint or hinge parts or joint or hinge projections 13a and 14a, which enable the base plates 13 and 14 to be pivotably or rotatably mounted on the wedge elements 30 and 40, are arranged such that they protrude from both sides of the upper ends of the base plates 13 and 14, and joint or hinge sections 30c and 40c, on which the joint or hinge projections 13a and 14a are pivotably mounted, are formed on the wedge elements 30 and 40.Furthermore, receiving holes 30d and 40d are provided as recesses for receiving all or parts of the elastic elements 15 for mounting the elastic elements 15 on the wedge elements 30 and 40. Therefore, as is usual when no braking operation is performed, the lower ends of the base plates 13 and 14 and the brake pads 11 and 12 are arranged such that they protrude towards the disc 10 due to the elastic restoring force of the elastic elements 15. Then, during a braking operation, the elastic elements 15 are deformed and received in the receiving holes 30a and 40d, and simultaneously the base plates 13 and 14 and the brake pads 11 and 12 are pivoted centering around their upper ends and assume a position parallel to the disc 10, and in this state the brake pads 11 and 12 rub against the disc 10 and generate a braking force, as shown in Fig. 3. As described above, the lower ends of the brake pads 11 and 12 are normally positioned, when no braking is performed, so that they protrude towards the disc 10. Thus, although friction occurs between the disc 10 and the brake pads 11 and 12, the contact areas between the disc 10 and the brake pads 11 and 12 are limited to the edges of the lower ends of the brake pads 11 and 12. Consequently, the frictional force between the disc 10 and the brake pads 11 and 12 is very small. Therefore, an unintended braking action resulting from movement of the brake pads 11 and 12 in the direction of rotation of the disc 10 is prevented by the frictional force between the disc 10 and the brake pads 11 and 12. As can be seen from the above description, in a disc brake for vehicles in accordance with an embodiment of the present invention, even if friction occurs between a disc and brake pads under the condition that no braking operation is carried out, the friction is limited to areas between the edges of the lower ends of the brake pads and the disc, thereby reducing a frictional force between the disc and the brake pads and thus preventing unintentional braking. Although a few embodiments of the present invention have been shown and described, it will be clear to those skilled in the art that modifications to these embodiments can be made without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

Disc brake for vehicles comprising: a disc (10) which is rotated together with a wheel of a vehicle; a pair of brake pads (11, 12) which are arranged opposite each other on both sides of the disc (10); and a pair of wedge elements (30, 40) which are mounted on the rear sides of the brake pads (11, 12), wherein the upper ends of the brake pads (11, 12) are each pivotably attached to the wedge elements (30, 40) and the lower ends of the brake pads (11, 12) are supported by elastic elements (15) such that they project towards the disc (10). Disc brake for vehicles according to claim 1, which further comprises a pair of base plates (13, 14) which are attached to the rear sides of the brake pads (11, 12), wherein the upper ends of the base plates (13, 14) are each pivotably attached to the wedge elements (30, 40) and thus the brake pads (11, 12) are pivotably connected to the wedge elements (30, 40) by the base plates (13, 14). Disc brake for vehicles according to claim 2, wherein: articulating or hinge projections (13a, 14a) for rotatably or pivotably mounting the base plates (13, 14) on the wedge elements (30, 40) are each arranged such that they protrude from both sides of the upper ends of the base plates (13, 14); and articulating or hinge sections (30c, 40c) on which the articulating or hinge projections (13a, 14a) are pivotably or rotatably mounted are formed on the wedge elements (30, 40). Disc brake for vehicles according to claim 1, wherein receiving holes (30d, 40d) for receiving the elastic elements (15) are provided as recesses on the wedge elements (30, 40).

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