Coating cylinder bores with ultra thin solid lubricant phase

Details Coating cylinder bores with ultra thin solid lubricant phase Coating cylinder bores with ultra thin solid lubricant phase

1999-07-09

2001-03-06

Parker, Fred J. (Department: 1762)

Coating processes

Interior of hollow article coating

Spraying

C427S239000, C427S327000, C427S421100

Reexamination Certificate

active

06197370

ABSTRACT:

TECHNICAL FIELD
This invention relates to the technology of coating cylinder bores and, more particularly, to coatings deposited in an ultra thin and uniform thickness while containing solid lubricant particles.
DISCUSSION OF THE PRIOR ART
Early bore coatings for automotive aluminum cylinder bores were created by use of an anodizing process (electro/electroless deposition) which resulted in a high nickel alloy, Nikasil; disadvantages of this process were higher friction, increased requirements for plant space and processing time, and higher investment and processing costs. Subsequent attempts to reduce friction while improving reliability involved use of cast iron liners or the application of cylinder bore coatings using standard spray paint equipment. When spray painting, a nozzle for the spray equipment was held at the mouth of the bore and the nozzle was articulated to achieve a 360° rotated deposition coating. Unfortunately, such equipment was cumbersome to manipulate and resulted in the coating being unusually thick (see U.S. Pat. Nos. 5,482,637 and 5,363,821).
Coating of aluminum cylinder bores have been recently carried out with thermal spray techniques, such as plasma arc and wire arc, to achieve a highly adherent coating that can withstand the demanding high temperature environment of an engine cylinder. The equipment to carry out such coating technique is complex and requires considerable expertise in controlling the coating because it is carried out in an enclosed, or hidden, environment (see U.S. Pat. No. 5,358,753). This technology is in its earliest stages of implementation dedicated to high volume production and is not suitable for small shop applications, such as engine repair or racing shops involving a small number of engines.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved method of coating cylinder bores by (i) depositing the solid lubricant phase from a fine mist of emulsion droplets formed in a hollow conical spray pattern, and (ii) controlling the movement of the spray pattern across the bore interior to achieve extremely accurate coating thickness without the need for subsequent finish honing.
It is also an object of this invention that equipment needed to carry out such method be relatively inexpensive, capable of very high production rates and require low to moderate floor space, and thus make the method implementable in existing shops or plants.
The method of this invention that achieves such object comprises the steps of (a) preparing the cylinder bore surface to expose fresh metal free of contamination, (b) generating a hollow conical spray consisting of fine mist droplets of a solid lubricant emulsion, the conical spray having an effective base with a diameter greater than the diameter of the cylinder bore and (c) moving the apex of the conical spray along the axis of the bore at a uniform speed to deposit a coating of the emulsion on the interior of the cylinder bore in a thickness no greater than 20 microns.
The invention in another aspect is an apparatus to coat cylinder bores with precise thickness and adhesion, comprising: (a) a nozzle for effecting a hollow conical spray pattern of an emulsion about an axis, (b) a highly pressurized supply of emulsion to the nozzle, the emulsion containing solid lubricant in fluid suspension and (c) means for controllably moving the nozzle within the cylinder bore to deposit a uniform coating of the emulsion preferably in the thickness range of 5-15 microns with flexibility for greater thicknesses up to 30 microns should it be desired.


REFERENCES:
patent: 4063686 (1977-12-01), Willis
patent: 4335677 (1982-06-01), Nagata et al.
patent: 5271967 (1993-12-01), Kramer et al.
patent: 5303141 (1994-04-01), Batchelder et al.
patent: 5358753 (1994-10-01), Rao et al.
patent: 5363821 (1994-11-01), Rao et al.
patent: 5482637 (1996-01-01), Rao et al.

Affiliated with

Also associated with

Rating

Coating cylinder bores with ultra thin solid lubricant phase does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Coating cylinder bores with ultra thin solid lubricant phase, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating cylinder bores with ultra thin solid lubricant phase will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2444834