Patent Application
20050161297
1. Field of Inventions
The present inventions relate generally to brake pads and brake pad backing plates.
2. Description of the Related Art
Brakes, which are used to control the speed of a wide variety of vehicles, commonly include a brake pad that engages a rotor. The brake pads consist of friction pad and a backing plate that is used to mount the brake pad on the brake. The backing plate/friction pad connection must be very secure because of the high levels of shear and tensile forces that are applied to the friction pad by the rotor, vehicle vibrations, etc. Some conventional methods of securing the friction pad to the backing plate involve molding the friction pad onto the backing plate. Frequently, discontinuities are formed on the surface of the backing plate in order to increase the surface area of the backing plate/friction pad bond and to create mechanical interference between the two.
The present inventor has determined that conventional methods of securing the friction pad to the backing plate, including the formation of the the backing plate itself, are susceptible to improvement. For example, the present inventor has determined that the conventional method of forming discontinuities on the backing plate, i.e. forming the discontinuities by punching or gouging the backing plate after the backing plate has been stamped out of a sheet of metal, is unnecessarily difficult and expensive. The present inventor has also determined that the configuration of the protrusions or other discontinuities on conventional backing plates is susceptible to improvement.
A method in accordance with a present invention involves cutting a brake pad backing plate out of a sheet having a plurality of discontinuities formed therein. A brake pad may be manufactured by subsequently securing a friction pad to the brake pad backing plate. There are a number of cost saving advantages associated with such a method. For example, it is much easier to form discontinuities in a large sheet and then form brake pads from the sheet than it is to form brake pads from and sheet with no discontinuities and then form discontinuities in each of the brake pads individually. Additionally, the discontinuities may be formed during the sheet formation process for further cost savings.
A brake pad backing plate in accordance with a present invention includes protrusions with a slanted parallelepiped shape. Such protrusions increase the bonding surface area of the backing plate and provide overhangs which act as hooks to mechanically engage the friction pad after bonding.
The above described and many other features and attendant advantages of the present inventions will become apparent as the inventions become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.
Detailed description of embodiments of the inventions will be made with reference to the accompanying drawings.
FIGS. 11A-C are side views of steps in a method in accordance with an embodiment of a present invention.
The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions.
As illustrated for example in
The protrusions 104, which are also substantially identical to one another in the exemplary implementation, each include a planar top surface 112 and four (4) side surfaces 114-120 (
In some embodiments of the present brake pad backing plate, at least a portion of the backing plate protrusions will have a slanted, parallelepiped shape. The exemplary protrusions 104, for example, are configured such that the portion of the protrusion between the top surface 112 and the plane defined by the line at the intersection of the side surface planar portions 118a/118b and the line at the intersection of the side surface planar portions 120a/120b has a slanted parallelepiped shape. [Note
With respect to materials and dimensions, the overall size of the brake pad backing plate 100 will depend on the intended application, as will the size and shape of the protrusions, the angles discussed above, and the material from which the backing plate is formed. In one exemplary implementation, which may be used in automotive applications, suitable materials include metals (such as 1010 steel), organics, ceramics, metal composites, plastics and high temperature fiber reinforced resin composites. The brake pad backing plate 100 will be about 2 to 15 inches wide (about 4.9 inches in one specific embodiment) and about 1 to 6 inches tall (about 2.6 inches in one specific embodiment), measured at the widest and tallest points. The thickness will be about 0.150 and 0.400 inches (and about 0.26 inches in one specific embodiment), measured from the top surfaces 112 of the protrusions 104 to the rear side 107. The protrusions 104 are about 0.04 to 0.12 inches high measured from the front side of the base member 102 to the top surfaces 112. The top surfaces 112 of the exemplary protrusions are square and are about 0.24 to about 0.26 inches in length and width. The distance between adjacent top surfaces 112 is about 0.04 to 0.12 inches. The angles α1 and α2 are preferably, but not necessarily, equal and about 30° to about 60°, the angles β1 and β2 are preferably, but not necessarily, equal and about 120° to about 150°, and the angles θ1 and θ2 are preferably, but not necessarily, equal and about 120° to about 150°. The dimensions above may, of course, be increased and decreased as applications so require.
There are, of course, an almost endless variety of alternative configurations. For example, the protrusions 104 my be made either larger or smaller (both in height and, when viewed in plan, surface area), the angles may be varied, the shape of the top surfaces 112 may be other than square (such as triangular or rectangular), the size and shape of the protrusions may be varied over the backing plate 100, and the distances between adjacent protrusions may be varied. The orientation of the protrusions 104 (i.e. the direction that the overhangs 122 and 124 face) may be adjusted as necessary. Additionally, the overall shape of the backing plate 100 could be curved instead of planar.
Turning to the channels 108 and 110, and given the shapes of the side surfaces 114-120, the channels are each generally defined by three planar walls, with gaps in the planar walls between the protrusions 104. The channels 108 and 110 could, alternatively, be formed with additional planar walls by, for example, splitting the planar portions 118b and 120b into two planar portions arranged at an angle to one another. The channels 108 and 110 could also have a continuous curved shape with two planar portions such as, for example the shape of a “U” that is oriented with the vertical portions angled in a manner similar to the side surfaces 114 and 116 and side surface planar portions 118a and 120a.
As illustrated for example in
The exemplary brake pad backing plate 100 may be manufactured in a variety of ways. One example of a manufacturing method in accordance with a present invention, which is well suited for metal backing plates, is illustrated in
Referring first to
A plurality of the exemplary backing plates 100 may be formed from the backing plate sheet 306 by cutting portions out of the sheet that are in the shape of the backing plates. Stamping is one method of cutting portions out of the backing plate sheet 306. As illustrated for example in
There are a number of benefits associated with the present method of manufacturing brake pad backing plates. For example, conventional processes frequently involve rolling a slab into a smooth sheet, stamping parts out of the sheet, and then using a punching or gouging process to roughen the parts and complete backing plates. The present method eliminates the post-stamping punching or gouging steps by forming the protrusions 104 and channels 108 and 110 during the formation of the metal sheet from which the backing plates will ultimately be stamped. Not only is it easier to form protrusions or other discontinuities in one large sheet, as compared to a plurality of small parts, the present method forms the discontinuities as during steps in the rolling process that would have been performed anyway by simply replacing the conventional dies at the end of the rolling process with dies that will form discontinuities. As a result, the present method provides substantial cost savings as compared to conventional methods.
Although the present inventions have been described in terms of the preferred embodiments above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art.
By way of example, but not limitation, the exemplary brake pad backing plate and brake pad illustrated in
It is intended that the scope of the present inventions extend to all such modifications and/or additions and that the scope of the present inventions is limited solely by the claims set forth below.
