Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reexamination Certificate
2001-12-11
2004-10-12
Colaianni, Michael P. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C264S279000
Reexamination Certificate
active
06803008
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method of reinforcing gears and various other parts having surfaces with complex geometries which are subject to wear. More particularly, this invention relates to a method for producing a reinforced part having a resin-rich skin applied to selected wear surfaces to provide increased lubricity and/or extended use. This invention also pertains to a method for providing a working part such as a gear having a resin-rich skin integrally attached thereto such that the resin-rich skin overlies the wear surface of the resulting part. This present invention is also directed to parts made of a reinforced material, such as gears having a resin-rich coating integrally bonded thereon.
BACKGROUND OF THE INVENTION
In devices such as automotive vehicles, numerous subassemblies require the use of moving parts which must have durable wear surfaces in order to provide failure-free function for prolonged periods up to and including the useful life of the associated automotive vehicle. It is also desirable to have the moving parts in the automotive subassemblies weigh as little as possible to reduce overall vehicle weight. Hence many moving parts with exposed wear surfaces are manufactured from polymeric materials where possible.
Polymeric parts can have drawbacks. Materials such as acetals exhibit good lubricity and wear resistance but can be inappropriate for use in intricate parts such as gears and the like. Parts manufactured from polymers such as acetals can exhibit creep and deformation when left under load. Additionally, polymeric materials such as acetals can shear under the load stresses possible in the subassembly environment. It can be appreciated that even small amounts of creep or shear can compromise the functionality of the gear or other part. Even small deviations or deformities in the geometry of the part can result in deviations beyond commonly accepted tolerances with deleterious results on the associated subassembly.
To mitigate this problem, parts with close tolerances or other dimensional criticalities can be manufactured from filled or reinforced polymeric materials. Reinforced polymers generally contain suitable fibrous or particulate reinforcement material such as glass, carbon fibers or the like. Use of acetal or other polymers reinforced with a suitable material such as glass fibers or the like has been proposed. Unfortunately, reinforcement does not address all problems inherent with such parts and presents additional problems when used.
Reinforced polymers exhibit increased coefficients of friction at the surface of the manufactured part. In parts such as worm gears and the like, increases in coefficients of friction can translate into increased surface wear and premature part failure. Thus, it is highly desirable that the material of construction be one which will provide a lubricious wear surface at the point of contact between the polymeric part and any mating member.
Attempts have been made to construct parts composed of reinforced polymeric material which have critical contact surfaces characterized by increase lubricity. Unfortunately, parts so constructed are prone to premature surface wear due to any of a number of failure phenomena including but not limited to shear separation and/or erosion. Eventually the underlying reinforced material is exposed with all of the problems attendant thereto.
Thus it would be desirable to provide a part having a body which could be advantageously constructed from reinforced polymeric material. It is also desirable that such a part have a suitable lubricous outer wear surface integrally connected to the reinforcing material to provide lubricity and suitable protection from excessive wear which can occur when mating parts come into contact with the polymeric part of the present invention. It is desirable that this reinforcing lubricious surface be located at discrete regions of the part as required. It is also desirable that the resulting polymeric part have any number of irregular geometric surfaces with an essentially uniform layer of lubricious polymeric coating overlying the irregularities as required or desired. Finally, it is also desirable to provide a method whereby such parts could be economically and predictably be made.
SUMMARY OF THE INVENTION
The invention provides a method of producing a part integrating a layer of a resin-rich material to a substrate in a process that produces a molded device. Such molded device or part would be suitable for use as a part in various high-wear environments such as mechanical subassemblies.
In the method of the present invention a film of resin-rich material is installed within a mold die. A volume of substrate is then introduced into the mold die in a molten state, preferably at a temperature above the melting point of the resin-rich material. The volume of molten substrate is introduced into the mold die under pressure through injection gates or orifices. The volume introduced has sufficient heat to melt the resin-rich film and to permit the substrate to remain molten long enough to deform the melted resin-rich material against the inner surface of the mold die. Introduction of the molten substrate occurs at a location and in a manner such that the resinous material is interposed between the inner surface of the mold die and the introduced molten substrate. The materials are then allowed to cool to solidify into the molded device. The resulting device possesses a relatively uniform resin-rich layer in a contoured, integrally-bonded relationship to the molded substrate.
The resin-rich material can be positioned in the mold die by any suitable means. If desired or required, the resin-rich material can be installed into mold die as a sheet. The resin-rich material can be preheated to a temperature below its melting and/or deformation point prior to introduction of the substrate material to the mold die. Alternately, the resin-rich material can be installed by deposition in preliminary contact with the internal surface of the mold die by a suitable deposition process. Examples of suitable processes include electrostatic deposition where suitably charged polymeric particles are electrostatically affixed to the mold surface. It is also within the purview of this invention to install the resinous material in the mold device by spraying melted or semi-melted particles of the resin-rich polymeric material onto the surface of the die mold with the surface being held at a temperature sufficient to permit the material to initially adhere and solidify on the surface. The mold die can then be filled with a molten substrate at a temperature sufficient to cause the particles to melt (or re-melt) in a manner that achieves integral boding of the resinous material to the introduced substrate material. The level of bonding achieved is to a degree greater than initial adhesion to the die mold surface, and solidifies the substrate such that the polymeric material bonds with the substrate.
REFERENCES:
patent: 4681712 (1987-07-01), Sakakiara et al.
patent: 5354532 (1994-10-01), Nakai et al.
patent: 5587209 (1996-12-01), Soga et al.
patent: 5908671 (1999-06-01), Tanaka et al.
patent: 6086810 (2000-07-01), Inagaki et al.
patent: 6492000 (2002-12-01), Matsuki et al.
patent: 42 08 276 (1993-09-01), None
patent: 101 19 235 (2001-10-01), None
patent: 0 739 706 (1996-10-01), None
patent: 0 1896 869 (1999-02-01), None
patent: 0 980 746 (2000-02-01), None
patent: 2 300 587 (1996-11-01), None
patent: 62-095209 (1987-05-01), None
A copy of the International Search Report dated May 2, 2003 is enclosed.
Colaianni Michael P.
Fontaine Monica A.
Lewis J. Gordon
Valeo Electrical Systems, Inc.
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