Clearly Stated FACTS in Bendix Own Filed Patent say Properly Performed Prestressing IS Necessary to insure Public Safety and is NOT OPITIONAL.
Various approaches have been considered for such redesigns, such as using materials other than the usual cast iron, using a smaller diameter brake rotor, and designing the calipers to be thinner in the radial direction to fit within a wheel rim. The
common theme among the alternatives is attempting to decrease the radial height of the brake caliper, typically by removing material from the portion of the caliper which bridges over the outer radius of the brake rotor (i.e., the portion of the caliper
between the brake application side and the reaction side of the caliper). None of these solutions has yet to provide a design without undesirable compromises, such as prohibitive cost (due to, for example, the use of higher strength, higher cost
materials) or insufficient strength and/or fatigue life due to unacceptably thin caliper sections.
Engineering calculations and testing have shown that when a brake caliper is loaded during brake application, there are regions of very high stress in and near the areas of the brake caliper which reach over the outer radius of the brake disk.
Calculations have demonstrated that when the amount of cast iron in the cross-disk region of a brake caliper is reduced in order to obtain sufficient wheel rim envelope clearance, the stress levels in cast iron brake calipers manufactured using
conventional manufacturing methods are so high as to significantly reduce the fatigue life of the caliper, to the point that adequate caliper life cannot be assured.
Typical approaches to increase fatigue life include increasing the amount of material present in the highly-stressed region; modifying the geometry of the component to further distribute and reduce stresses; moving to higher cost, higher strength
materials such as steel alloys, and various surface treatments.
U.S. Pat. No. 5,841,033 shows a method of improving fatigue performance in steel components (a much more ductile material than cast iron, which is brittle and unforgiving of excessive deflection). In this method, a compressive force is applied to
specific points along the surface of the components to pre-stress the component in localized areas. This pre-stress is not applied over the entire surface of the components, or to inner regions.
http://www.google.com/patents/US8423191
On Wednesday, May 18, 2016 at 7:45:54 AM UTC-5,
fuller...@hotmail.com wrote:
In one embodiment, a cast iron brake caliper is designed with a thinner than customary section which bridges the gap over a brake rotor between the brake actuator and reaction sides of the caliper. In the pre-stressing process of the present invention,
the cast iron caliper is then subjected to a pre-stressing loading in a highly controlled manner to alter the caliper's material structure in the most highly stressed region(s) of the caliper. Preferably, the load is applied to the caliper in the same
manner as during brake use in an installed vehicle brake application, e.g., the portions of the caliper which are alongside a brake rotor during brake application are pushed apart in the same manner was when reaction forces are generated during brake
application. Once the load is increased to a predetermined level, the load is maintained for a predetermined period, and then the load is decreased in a controlled manner. The pre-stressing loading cycle may be repeated one or more times.
The load applied in the inventive pre-stressing process is set high enough to cause elastic deformation in the majority of the brake caliper, and further high enough to also cause a very limited amount of plastic deformation to occur in the very
highest-stressed regions of the caliper (i.e., exceeding the yield limit in these highest-stressed regions, resulting in plastic elongation of the caliper material). The load must be set high enough to cause the desired plastic elongation, but must also
be controlled so that the load is neither too high nor applied for too long a period that the brake caliper structure begins to fail, for example by exceeding the plastic elongation limit (i.e., the ultimate strength, which is the point at which plastic
elongation ceases and failure of the material begins) - a point which frequently (but not always) is accompanied by the development of cracks in the material.
LSW ADB22x Station #1 PreStress QR Code Scanner Safety Net.
Thermal resin transfer vinyl sticker with dirty thermal print head.
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