Thermal spraying apparatus

Abstract

A thermal spraying apparatus that is capable of effectively preventing the adhesion of spray fumes to unsprayed regions of a bore surface during arc spraying is provided. To this end, a thermal spraying apparatus 10 comprises a spray gun 6 that moves within a cylinder bore. The spray gun 6 has at one end thereof a first discharge opening (atomizing nozzle 62) that faces a direction that is orthogonal to the movement direction, has a second discharge opening (auxiliary nozzle 63) that faces a direction that is orthogonal to the nozzle 62, and has, at a predetermined region located further to the side in the movement direction of the spray gun 6 than the nozzle 62, third discharge openings (fume adhesion prevention nozzles 65) for discharging a fluid and that faces the same direction as the nozzle 62. A droplet, which forms as an arc spray wire material melts at the tip of the spray gun 6, is stretched with auxiliary air A1. By blowing atomizing air A2 onto the droplet, spray particles are formed and sprayed onto the bore surface. At the same time, fume adhesion prevention air A3 is blown towards the cylinder bore surface in synchrony with the spraying of the spray particles.

Description

TECHNICAL FIELD[0001]The present invention relates to a thermal spraying apparatus that forms a spray coating on an inner circumferential surface of a cylinder bore of an engine and the like.BACKGROUND ART[0002]On cylinder bore surfaces of cylinder blocks, spray coatings for improving the corrosion resistance, wear resistance, and the like of the bore surfaces are formed by thermal spraying techniques in which a combustion flame is generated by an arc, plasma, gas, or the like, various metals or alloys are instantaneously melted, and spray particles which have been atomized (micro-particulated) by compressed air are made to impact / solidify and adhere. Such thermal spraying is performed by moving a spray gun in a rotating posture between both ends of a cylinder bore as disclosed in Patent Document 1, for example. However, when the spray particles impact the bore surface, spattering of the spray particles occurs, which causes such problems as the adhesion of these reflected particles ...

AI Technical Summary

Benefits of technology

[0012]According to the thermal spraying method of Patent Document 2, the operation of attaching / detaching a masking member can be eliminated. However, it merely adjusts the spray angle. With this configuration, the adhesion of reflected particles and spray fumes to an unsprayed surface of a bore surface cannot be prevented completely. In addition, according to the thermal spraying method of Patent Document 3, although fumes adhered to a bore surface may be removed, it does not go so far as to prevent the adhesion of fumes and the like.

[0013]The present invention is made in view of the problems mentioned above. Its object is to provide a thermal spraying apparatus that is capable of, with a simple apparatus configuration, effectively preventing the adhesion of reflected particles and spray fumes to a cylinder bore surface during spraying.

Problems solved by technology

With this configuration, the adhesion of reflected particles and spray fumes to an unsprayed surface of a bore surface cannot be prevented completely.

In addition, according to the thermal spraying method of Patent Document 3, although fumes adhered to a bore surface may be removed, it does not go so far as to prevent the adhesion of fumes and the like.

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