Document NNekdnmO1Y83Vzz1Lk9EX5QOE

United States Patent 4,240,530 Page 5 of 6 The calotte-shaped embossings 7 and 8 in parts 3 and 2, respectively, are axially aligned. The part 3 is fcpnnged so that the raised portion of the embossings 7 engage the friction matenal and the recessed portion of the embossings face part 2 Part 2 of the carrier plate 1 is arranged so that the raised portion of the embossings 8 are received in the recessed portion of the embossings 7 m part 3 In this manner the raised portions of the embossings 7 on part 3 project into the friction matenal 5 and help resist shear stress imparted to the friction matenal 5 dunng braking Likewise, the nested relationship of the embossings 7 and 8 enable the earner plate 1 to resist the shear stresses imparted to part 3 dunng braking. Refemng to FIG 2, it can be seen that a thin bonding matenal 4 is inserted between and permanently bonded to parts 2 and 3 of the earner plate 1 In this way, parts 2 and 3 are joined to form the carrier plate 1. The matenal 4 is slightly compressible, vibration-damping, heat-insulating, elastic and nonswellable. A brake pad according to the instant invention can be manufactured as follows. Part 3 of the earner plate 1 which is closest to the friction matenal 5 is constructed from a steel plate three millimeters thick. Part 2 of the earner plate 1 is constructed from a steel plate 1 2 millimeters thick. Part 2 can also have the same length and width as part 3 and have bores coaxial with the bores 6 in part 3. A plurality of calotte shaped, axially aligned embossings 7 and 8 are formed on parts 3 and 2, respectively. The embossings have oblique centenng surfaces which are approximately eight millimeters in diameter and one millimeter m depth. After embossing the two metallic plates are degreased in the customary manner and an adhesive is put on both sides of part 3 and on the side of part 2 which faces part 3 A layer of cychzed rubber having a thickness of 0.15 millimeters is placed between the parts 2 and 3 of the earner plate 1. The parts 2 and 3 of the earner plate 1 are placed in a mold with the layer 4 therebetween. A friction jlining composition 5 is then poured into the mold Subsequently, the pressing process is earned out at a pressure between 500 and 700 kp/cm sup 2 and at a temperature between 150 degree, and 210 degree C for a cunng time of 2-12 minutes This is done in a smgle press die and in a single step The friction lining composition is shaped and formed to give the friction lining 5 and simultaneously the lining 5 is bonded to the earner plate 1 and the bonding layer 4 is bonded to the parts 2 and 3 to produce the unitized earner plate 1 Using this method, it has been found that the bonding layer 4 is non-swellable, that is to say, nonflowable, and the matenal is not pressed out from between the parts 2 and 3 dunng the pressing operation. Further, it has been found that dunng the pressing operation, the projections and recesses of the calotte-shaped embossings 7 and 8 precisely center parts 2 and 3 and prevent relative displacement of the parts. It has also been found that the bonding matenal 4 not only forms a vibration-dampmg and heat-insulating layer, but is also forms a wall having a uniform thickness between the parts 2 and 3. In this manner, metal-to-metal contact of the parts 2 and 3 is prevented at all places including adjacent the calotte-shaped embossings, with the result that no bndges are formed which can transmit vibration or heat. Since the bonding matenal 4 is very thin, it has been found that using the aforementioned dimensions the projections and recesses of the embossmgs 7 and 8 adequately engage each other and reliably absorb the shear forces ansing dunng braking, and that mutual displacement of the parts 2 and 3 is prevented. In actual tests in which the brake pad was stressed by sheanng forces which acted parallel to the contact surfaces, the shear forces reached 1870-2000 kp before failure These forces are considerably higher |han those customanly demanded by brake manufacturers and car manufacturers A vanety of matenals suitable for bonding layer 4 have been found One suitable matenal is rubbermodified asbestos having a thickness of 0 5 millimeters Another matenal is linen-fabnc impregnated http //oatft usnto eov/netacei/nnh-Parser?Sectl=PT02&Sect2=HTTOFF&u=/netahtrn1/<;ea 10/18/7003