Patent Application
20090050427
The present invention is predicated upon systems and methods for improving brake calipers and rotors and more specifically for improving brake caliper deflection and stress response characteristics.
Current vehicle designs have created a need for brake systems having relatively large rotors. In an effort to keep costs and system weights down, brake manufacturers have faced the grueling challenge of optimizing braking capability in larger systems without unduly adding mass or structures that occupy substantial volume. One approach to addressing this packaging issue has been to employ calipers with relatively thin bridges or other sections. However, it has proven difficult to achieve the proper desired balance of stiffness for such designs without involving intricate or costly structures that simultaneously address overhang, mass, thickness, rotor/pad clearance, and thermal dissipation considerations. Because poor performing calipers are a potential source of customer dissatisfaction resulting in warranty costs and loss of future sales, there continues to be a need for reliable calipers that are relatively easy to make.
Examples of efforts in the art toward caliper design are found in U.S. Patent Application Nos. 20050236237 and 20070051568 all herein incorporated by reference for all purposes.
The present invention meets the above, especially the need for improved brake caliper deflection and stress condition response needs, by providing an improved brake system for assembly into a vehicle structure. By way of summary, in one aspect, the present invention is directed to a brake caliper assembly that includes a finger portion including a first end that is free, a second end, an inner surface and an outer surface; a cylinder portion including a first end that is free, a second end, an inner surface and an outer surface; and a bridge portion, including an inner surface, an outer surface that connects with the second end of the finger portion at a finger corner region having an inner surface and an outer surface. The bridge portion also connects with the second end of the cylinder portion at a cylinder corner region having an inner surface and an outer surface. The resulting structure defines a continuous inner surface structure that includes the inner surfaces of each of the finger portion, the cylinder portion, the finger corner region, the cylinder corner region, and the bridge portion. The inner surface of at least one of the finger or cylinder corner regions includes an inclined surface that is generally flat for a span of at least about 2 mm.
In another aspect, the present invention contemplates a brake caliper assembly that includes a finger portion, a cylinder portion, and a bridge portion. The finger portion includes a first end that is free and a second end, and an inner surface and an outer surface. The cylinder portion includes a first end that is free and a second end, and inner surface and an outer surface. The bridge portion includes an inner surface and an outer surface for connecting with the second end of the finger portion at a finger corner region having an inner surface and an outer surface. Furthermore, the inner surface and the outer surface of the bridge portion are for connecting with the second end of the cylinder portion at a cylinder corner region that has an inner surface and an outer surface. Yet furthermore, the inner surface and the outer surface of the bridge portion are for defining a continuous surface that includes the inner surfaces of each of the finger portion, the cylinder portion, the finger corner region, the cylinder corner region, and the bridge portion. The inner surface of the finger corner region includes a first inclined surface having a first end and a second end, which surface is generally flat for a span of at least about 2 mm. The first end of the inclined surface is connected to the inner surface of the finger portion by a first arcuate surface that has a first radius. The second end of the inclined surface is connected to the inner surface of the bridge portion by a second arcuate surface that has a second radius that is different from the first radius.
In another aspect, the present invention contemplates a brake caliper assembly that includes a cast iron caliper body and a pad assembly including at least one friction member carried on a support plate that includes a corner region having a flat surface. The cast iron caliper body includes a finger portion including a first end that is free and a second end, and an inner surface and an outer surface, a cylinder portion including a first end that is free and a second end, and inner surface and an outer surface; and a bridge portion. The bridge portion has an inner surface and an outer surface for connecting with the second end of the finger portion at a finger corner region having an inner surface and an outer surface. Furthermore, the inner surface and the outer surface of the bridge portion are for connecting with the second end of the cylinder portion at a cylinder corner region having an inner surface and an outer surface. Yet furthermore, the inner surface and the outer surface of the bridge portion are for defining a continuous generally concave surface that includes the inner surfaces of each of the finger portion, the cylinder portion, the finger corner region, the cylinder corner region, and the bridge portion. The inner surface of each of the finger and cylinder corner regions includes an inclined surface having a first end and a second end, which surface is a generally flat machined surface which is substantially free of a mold texture, for a span of at least about 5 mm. The first end of the inclined surface of the finger corner region is connected to the inner surface of the finger portion by a first arcuate surface having a first radius. The second end of the inclined surface is connected to the inner surface of the bridge portion by a second arcuate surface having a second radius that is different from the first radius. The first end of the inclined surface of the cylinder corner region is connected to the inner surface of the cylinder portion by a first arcuate surface having a first radius, and the second end of the inclined surface of the cylinder corner region is connected to the inner surface of the bridge portion by a second arcuate surface having a second radius that is different from the first radius.
In yet another aspect, any of the aspects of the present invention may be further characterized by one or any combination of the following features: the inner surface of each of the finger and cylinder corner regions includes an inclined surface that is generally flat for a span of at least about 2 mm; the inclined surface is connected to the inner surface of the bridge portion by an arcuate surface; the inclined surface is connected to the inner surface of the at least one of the finger portion or the cylinder portion by a arcuate surface, and the inclined surface is connected to the bridge portion by another arcuate surface; the inclined surface is a machined surface, which is substantially free of a mold texture; the bridge portion and at least one of the finger portion or the cylinder portion are cast iron; the assembly further includes at least two opposing spaced apart friction members disposed between the cylinder portion and the finger portion; the assembly further includes a pad assembly including at least one friction member carried on a support plate that includes a corner region that includes a flat surface for generally opposing the flat surface of the finger corner region; the assembly further includes a pad assembly including at least one friction member carried on a support plate that includes a corner region that includes a flat surface that is substantially parallel to the flat surface of the finger corner region; the inner surface of the inboard corner region includes a first inclined surface having a first end and a second end, which surface is generally flat for a span of at least about 2 mm, the first end of the inclined surface being connected to the inner surface of the cylinder portion by a first arcuate surface having a first radius, and the second end of the inclined surface being connected to the inner surface of the bridge portion by a second arcuate surface having a second radius that is different from the first radius; the ratio of the radius of the arcuate surfaces in at least one of the corner regions is at least about 2:1; for at least one of the inclined surfaces, the width of the flat span of such inclined surface is larger than the value of each radius of the arcuate surfaces; in a brake-off position, the bridge portion includes a first end and a second end that are juxtaposed within a space defined by two opposing support plates having an inner face; or any combination thereof.
With reference to
The inner surface of at least one of the finger or cylinder corner regions includes an inclined surface that is generally flat for a span of at least 2 mm. Thus, for example, both the finger and the cylinder corner regions include an inclined surface 54, 56, respectively, that is generally flat for a span of at least about 2 mm and more specifically at least about 5 mm.
141 The inclined surface of the finger corner region, the cylinder corner region, or both may be connected to the inner surface of the bridge portion by an arcuate surface or one or more other generally flat surfaces. For example, as shown in
It is appreciated that by incorporating a corner region having chamfer (e.g., a flat surface between two different radii), the finger corner region, the cylinder corner region, or both may include a thicker section that is generally located between the outer surface and the inner surface of the respective corner region (e.g., finger corner region or cylinder corner region). A thicker section can improve stress conditions by reducing the occurrence of stress fractures, breakage, or both within the caliper body. The support plate of the pad assembly may also incorporate a chamfer (as discussed herein) to provide appropriate clearance between the finger corner region, the cylinder corner region, or both to the respective support plate having a chamfer corner portion.
In another embodiment of the present invention, the pad assembly is specifically configured to have substantially complementary geometry relative to the caliper. Accordingly, the caliper may further include a pad assembly including at least one friction member carried on a support plate that includes a corner region. In one aspect, the corner region of the pad includes a flat surface for generally opposing (e.g., substantially parallel) the flat surface of the corner region of the finger portion, the cylinder portion, or both.
Further, desired stress response characteristics may be achieved according to the teachings herein by juxtaposing the end of the bridge portion (as shown in
In general, the caliper bodies will be made by metal casting followed by machining for achieving the necessary structure detail. The inclined surfaces 54, 56 may be defined in the caliper bodies as a result of the casting, from a subsequent machining step, or both. Preferably, one or both of the inclined surfaces are mill-cut so as to define machined surfaces. Thus, the inclined surfaces (and optionally any associated arcuate end surfaces) will exhibit a topography that is substantially free of a mold texture (e.g., it will be free of a pebbled texture).
It is appreciated by incorporating chamfers in the corner regions of the caliper body and respectively to the support plates of the pad assemblies a reduction in caliper deflection and a reduction in stress of the caliper body is believed possible, as compared with a typical prior art structure such as shown in
Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components can be provided by a single integrated structure. Alternatively, a single integrated structure might be divided into separate plural components. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such features may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention.
The preferred embodiment of the present invention has been disclosed. A person of ordinary skill in the art would realize however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.
The present invention claims the benefit of the priority of the filing date of U.S. Provisional Application Ser. No. 60/957,339 filed Aug. 22, 2007, which is herein incorporated by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 60957339 | Aug 2007 | US |
