Patent Application
20130323525
This disclosure relates to a refractory interface coating applied to bi-metallic components of an automotive product.
Automotive products including, but not limited to, brake rotors, pulleys, brake drums, and transmission gears, may have a plurality of components composed of different materials that are interconnected. The components may be interconnected by a cast-in-place process, in which one component is cast over the other component to form a joint or interconnection.
During vehicle operation, thermal expansion and contraction may occur, as the temperature of each of the components may rise to an increased operating temperature during vehicle operation and fall to a decreased resting temperature during vehicle rest. The increase in temperature during vehicle operation may lead to thermal deformation and degradation of both the yield strength and tensile strength of the materials.
An automotive product having a plurality of components coated with a refractory interface coating is provided. The automotive product may include at least a first component and a second component.
The first component may be composed of a first high-density material. The first component may include an annular portion and a first flange member. The first flange member may include a first surface and a second surface and may be configured to extend radially from the annular portion. A plurality of mechanical engagement features may be formed upon and extend from the first surface and second surface of the first flange member.
The second component may be formed of a second lower-density material. The second component may include a hub portion and a second flange member. The second flange member may be configured to engage the first flange member at an interface with the plurality of mechanical engagement features, forming an interconnection between the first and second components. The second component may be integrally formed onto the first component in a cast-in-place or other process known in the art.
A refractory interface coating may be applied to the plurality of mechanical engagement features to improve the interface between the first and second components by providing an enhanced surface finish to limit friction, prevent metallurgical bonding between the first material and second material, provide a barrier against galvanic corrosion, and provide a thermal barrier between the first component and second component to guard against thermal deformation or change in dimension of the second component.
A method for making a bi-metallic automotive product is also provided. The method includes the steps of forming a first component utilizing a casting, machining, forging, or other suitable metal working process; applying a refractory interface coating to the plurality of mechanical engagement features of the first component; placing the first component in a first cavity of a molding machine; and injecting molten material into the cavity to envelop the first plurality of mechanical engagement features, thereby casting the second component about the first component.
The above features and advantages, and other features and advantages, of the present invention are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the invention, as defined in the appended claims, when taken in connection with the accompanying drawings.
Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “downward,” “upward,” “top,” bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the invention. The following description and Figures refer to example embodiments and are merely illustrative in nature and not intended to limit the invention, its application, or uses.
Referring to the Figures, wherein like reference numbers correspond to like or similar components throughout the several views, an automotive product 100 having a plurality of components 101, 102, which may be coated with a refractory interface coating 104 is provided. The automotive product 100 may include, but is not limited to, applications including brake rotors, a pulley, a sprocket, brake drums, transmission gears, or transmission gear assemblies. An example of the automotive product 100, is generally shown as a brake rotor assembly in
Generally, referring to
Referring to
The first component 101 may further include a first flange member 108. The first flange member 108 may be configured to extend radially from the first friction surface 106 and annular portion 105. The first flange member 108 may be configured to extend from a first flange proximal end 112, proximate the first friction surface 106, to a first flange distal end 113. The first flange member 108 may be further configured to have a first surface 114, a second surface 115, and an inner surface 116. The inner surface 116 may further be formed at the first flange distal end 113. A plurality of mechanical engagement features 109, such as teeth or the like, may be formed on and protrude from the first surface 114 and the second surface 115. The plurality of mechanical engagement features 109 may be equally spaced or randomly staggered circumferentially, upon the first flange member 108. The plurality of mechanical engagement features 109 may be configured to engage the second component 102.
Referring to
An engagement slot 124 may be defined by the second flange member 121 between the at least two second flange surfaces 122, 123. The engagement slot 124 may include a first engagement slot surface 125 and a second engagement slot surface 126. The second flange member 121 may be configured to engage and trap the first flange member 108 within the engagement slot 124, forming an interconnection 103 between the first component 101 and the second component 102. The interconnection 103 of the first component 101 and second component 102 may be formed with the plurality of mechanical engagement features 109 and the engagement slot 124 to limit the rotation of the second component 102 relative to the first component 101 during vehicle operation. The second component 102 may be integrally formed onto the first component 101 in a cast-in-place process or other process known in the art.
Referring generally to
Generally, in bi-metallic automotive product applications, heat transfer from the first and second frictional surfaces 106, 107 of the first component 101 of a first high-density material, to the second component 102, of a lower-density material can cause the second component 102 to deform, change dimension, and degrade at temperatures above about 150° C. The temperature at the interconnection 103 between the first component 101 and second component 102 can reach temperatures in excess of about 200° C., during vehicle operation. Thus, the application of a refractory interface coating 104 at the interconnection 103 between the first component 101 and the second component 102, for example, at the plurality mechanical engagement features 109, may absorb heat generated by the application of the brake pads (not shown) to the first and second friction surfaces 106, 107 of the first component 101. The refractory interface coating 104 may limit heat transfer from the first component 101 to the second component 102, thereby functioning as a thermal barrier, which may allow the second lower-density material of the second component 102 to maintain dimension, yield strength, tensile strength, and elongation during vehicle operation.
The application of a refractory interface coating 104 at the interconnection 103 between the first component 101 and the second component 102 may also provide several other advantages to bi-metallic automotive products 100. The application of the refractory interface coating 104 may enhance the surface finish of each of the respective first and second components 101, 102, which may limit friction at the interface between the first component 101 and the second component 102 at the interconnection 103, and provide a barrier against galvanic corrosion.
An additional advantage of applying the refractory interface coating 104 at the interconnection 103 between the first component 101 and the second component 102 may be the prevention or limiting of metallurgical bonding between the first high-density material of the first component 101 and second lower-density material of the second component 102.
A method for making a bi-metallic automotive product 100 is also provided. The method includes the steps of forming a first component 101 utilizing a casting, machining, forging, or other suitable metal working process; applying a refractory interface coating 104 at the interconnection 103 between the first component 101 and a second component 102; placing the first component 101 in a first cavity of a molding machine; and injecting molten material into the cavity to envelop the first plurality of mechanical engagement features 109 thereby casting the second component 102 about the first component 101.
The detailed description and the drawings or figures are supportive and descriptive of the invention, but the scope of the invention is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed invention have been described in detail, various alternative designs and embodiments exist for practicing the invention defined in the appended claims.
