This invention relates to vehicle disc brake pads, and more particularly, to slotted vehicle disc brake pads.

BACKGROUND

Disc brake pads are used in a variety of vehicles of varying size, including motorcycles, automobiles, and tracks, and generally include a backing plate and a friction pad attached to the backing plate. The size and shape of the brake pads, backing plates, and/or friction pads may vary depending upon the size and/or weight of the vehicle with which they are used. One or more features such as slots may be included in the friction surface to aid in cooling. Particular configurations for the slots may amplify the speed and/or amount of airflow, thereby improving the cooling effect.

SUMMARY According to one embodiment, there is provided a brake pad comprising a backing plate and a friction pad. The friction pad has a friction surface defined at least in part by a peripheral edge and a slot formed in the friction surface. The peripheral edge has a top radius, a bottom radius, and sides between the top radius and the bottom radius. The slot includes a main body portion and a pronged angled cutout portion that interfaces with the peripheral edge.

According to another embodiment, there is provided a brake pad comprising a backing plate and a friction pad. The friction pad has a friction surface, a first curved slot formed in the friction surface, and a second curved slot formed in the friction surface. Each curved slot has a main body portion and a radial arc extension having an inner circumference. A portion of a top radius of the friction pad and the inner circumferences of each radial arc extension form a continuous cooling arc.

BRIEF DESCRIPTION OF THE DRAWING

Preferred exemplary embodiments of the invention will hereinafter be described in conjunction with the appended drawing containing a Figure that is a partial perspective view of a brake pad according to one embodiment.

. i - DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The friction pad embodiments disclosed herein may be used in various disc brake pad designs and in various vehicle applications to help improve the airflow across the friction material. The inclusion of a slot with an angled cutout that interfaces with a top 5 radius of the friction pad can help increase the amount of air and/'or the speed of air which cools the friction materia] . Other various slot features discussed herein can also help promote cooling of the friction material. The presently disclosed friction pad may help extend the useful life of the brake pad, for example, by improving the thermal management of the brake pad via the advantageous airflow patterns that may be developed ! o d uri ng us e of th e brake pad .

Referring to the Figure, there is shown a disc brake pad 10. The brake pad 10 includes a backing plate 12 and a friction pad 14. The backing plate 12 includes a front face 16 and a periphery 18. The friction pad 14 is attached to the front face 16 of the backing plate 12 and includes a friction surface 20 facing away from the backing plate 12,

15 a peripheral sidewall 22, and a peripheral edge 24 comprising a top radius 26, a bottom radius 28, and sides 30, 32. When installed in a braking system, typically the top radius 26 is situated toward the outer diameter of the rotor and the bottom radius 28 is situated toward the center of the rotor. The friction surface 20 has a generally defined center portion 34 which is framed by slots 36, 38. Various slot features described herein can help 0 improve the cooling effect as compared with more standard slots or grooves formed in the friction surface of prior art disc brake pads. The backing plate 12 or the friction pad 14 may also include other features such as one or more chamfered surfaces 40, which may be flat or curved surfaces, or features not illustrated in this particular embodiment, such as caliper attachment projections, wear sensors, etc. 5 The slots 36, 38 may be molded in, or formed in a secondary operation in which a partially or fully formed friction pad 14 is routed or otherwise grooved along a desired path. CNC routing of the slots 36, 38 is one such method. Including a curve in one or more portions of the slots 36, 38 can help increase the surface area exposed to the cooling airflow. Accordingly, the slots 36, 38 may follow a mathematically defined curved path, 0 such as a simple sinusoidal or more complex curve defined by a polynomial, curve fit, or other formula or numerically specified path. The slots 36, 38 each generally include a mam body portion 42 and an angled cutout portion 44. The main body portion 42 of each slot 36, 38 has an inner circumference 46 and an outer circumference 48 with a sloped internal wall 50 therebetween. The sloped internal wall 50 is generally U-shaped; however, in this embodiment, a nadir 52 of each internal wall 50 is skewed toward the outer circumference 48 and the respective side 30, 32. Each sloped internal wall 50 is angled toward the center portion 34 of the friction pad (i.e., a line tangential to the nadir 52 is angled with respect to the friction surface 20), which may help encourage desirable airflow paths, which will be detailed further below. The sloped internal wail 50 may include a chamfered interior edge 54 and/or a chamfered exterior edge 56 to ease the transition between the slot 36, 38 and the friction surface 20. The main body portion 42 may further include an exit wall 58 which interfaces with the bottom radius 28 of the friction pad 14. As with the sloped internal wall 50, the exit wail 58 may include a chamfered interior exit wall edge 60 and/or a chamfered exterior exit wall edge 62.

Slots 36, 38 may also include an angled cutout portion 44 which interfaces with the top radius 26 of the friction pad 14 at the peripheral sidewall 22. The angled cutout portion 44 is completely recessed with respect to the friction surface 20, and in this embodiment, has two prongs comprising a radial arc extension 64 and a convex shoulder extension 66. A junction wall 68 is situated between the main body portion 42, the radial arc extension 64, and the convex shoulder extension 66. A vertex 70 is situated where the junction wall 68, the radial extension 64, and the convex shoulder extension 66 meet. The junction wall 68 may include one or more chamfered junction wall edges 72 to ease the transition between the angled cutout portion 44 and the friction surface 20. The radial arc extension 64 and/or the convex shoulder extension 66 may also include one or more chamfered edges. As shown in the figure, the angled cutout portion 44 extends into less than the top quarter of the friction pad 14, which provides for a larger circular center portion 34 available for contacting the rotor.

The radial arc extension 64 may include an inner circumference 74 and an outer circumference 76, and the convex shoulder extension 66 may include an inner circumference 78 and an outer circumference 80. In one embodiment, the inner circumferences 74 of each radial arc extension 64 form a continuous cooling arc 82 with a portion of the top radius 26. Further, the convex shoulder extension can include an angled entry interface 84 and the radial arc extension may include a widened airflow interface 86. Certain geometrical relationships may help encourage airflow into and/or out of the angled entr ' interface 84 or the widened airflow interface 86, For example, in the illustrated embodiment, the vertex 70 is formed between the inner circumference 78 of the convex shoulder extension 66 and the outer circumference 76 of the radial arc extension 64. An angle Θ at the vertex 70 may be between about 60° and 70°, inclusive, or more particularly, about 65° in one embodiment, to encourage airflow into and/or out of the angled entry interface 84 or the widened airflow interface 86.

Various features of the angled cutout portion 44 can encourage desirable airflow patterns when the brake pad 10 is in use. A first airflow stream 88 and a second airflow stream 90 are illustrated in the Figure. As shown, the first airflow stream 88 enters the slot 36 at the angled entry interface 84 of the convex shoulder extension 66. Upon contact with the junction wall 68, at least part of the airflow stream 88 is deflected toward the radial arc extension 64. The airflow stream 88 continues toward the widened airflow interface 86 to help cool the top radius 26 along the continuous cooling arc 82. At least a portion of the airflow stream 88, along with the second airflow stream 90 may comprise captured airflow from the outer diameter of the rotor. As shown in FIG. 1, the angled cutout portion 44 of the second slot 38 may help draw the airflow stream 90 into the main body portion 42 to encourage airflow down to the bottom radius 28. Since the convex shoulder extension 66 of the second slot 38 projects further toward a center axis A of the friction pad 14, more of the airflow stream 90 may be encouraged to enter the main body portion 42 of the slot 38. Moreover, given that in this embodiment, the slots 36, 38 are symmetrical with respect to the center axis A of the friction pad 14, the continuous cooling arc 82 is also symmetrical, and more air or a higher speed air stream may be accessible to contact and cool the friction material. Any or all of the curved slot portions such as the radial arc extension 64, the convex shoulder extension 66, the continuous cooling arc 82, and/or the curvature of the main body portion 42, may encourage airflow via the Coanda effect, in which a fluid jet or air stream may be encouraged to attach or follow a convex surface. Moreover, one or more combinations of the various features, such as the first and second radial arc extensions 64 with the portion of the top radius 26 to form the continuous cooling arc 82, may encourage desirable airflow patterns. Additionally, the combination of features at the angled cutout portion 44, such as the radial arc extension 64, the convex shoulder extension 66, with the junction wall 68 therebetween, may facilitate more air or higher speed air to help cool the friction pad 14. It is to be understood that the foregoing is a description of one or more preferred exemplar) _' - embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

As used in this specification and claims, the terms "for example," "e.g.," 'Tor instance," "such as," and "like," and the verbs "comprising," "having," "including," and their other verb forms, when used in conj unction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.