Abstract: The adhesiveness of a thermal spray coating and a cylinder internal surface is improved by forming a sufficient roughened surface on an internal surface. A processing roller is installed on the main shaft of a processing device via a pressurizing mechanism. An uneven surface is provided on the external periphery of the processing roller. By pressing the processing roller against the internal surface while the roller rotates and moves, a fine unevenness that corresponds to the unevenness of the roller is formed on the cylinder internal surface. A thermal spray coating is formed on the internal surface where the inner surface has been roughened by forming the above-mentioned unevenness.

Abstract: A method for processing a cylinder block is disclosed, wherein a protrusion protruding toward a crankcase is provided at a crankcase-side edge of a cylinder bore and a sprayed coating is formed on an inner surface of the cylinder bore and an inner surface of the protrusion continuous with the inner surface of the cylinder bore. After forming the sprayed coating, at least part of the protrusion is removed together with the sprayed coating formed on the inner surface of the protrusion. Accordingly, even in the case of removing the edge portion of the cylinder bore on the crankcase side, a sufficient margin to be removed can be ensured while a reduction in size of the cylinder block is achieved.

Abstract: A method for processing a cylinder block is disclosed, wherein a protrusion protruding toward a crankcase is provided at a crankcase-side edge of a cylinder bore and a sprayed coating is formed on an inner surface of the cylinder bore and an inner surface of the protrusion continuous with the inner surface of the cylinder bore. After forming the sprayed coating, at least part of the protrusion is removed together with the sprayed coating formed on the inner surface of the protrusion. Accordingly, even in the case of removing the edge portion of the cylinder bore on the crankcase side, a sufficient margin to be removed can be ensured while a reduction in size of the cylinder block is achieved.

Abstract: A sprayed film forming method and apparatus in which the thickness of the sprayed film in a predetermined region is increased so as to unify the entire thickness. A sprayed film is formed at a cylinder bore inner surface while a spraying gun is moved in an axial direction during rotation inside the bore. Air inside the bore is sucked out to prevent foreign material from being caught in the sprayed film. The flow rate inside the bore tends to become higher at an axial end on a suction side, resulting in a thinned region. The supply speed of a wire serving as a spraying material to the spraying gun or the number of sprays in this region is higher than those at other portions. The thickness at the axial end of the bore is made equal while suppressing an increase in working time and spraying material used.

Abstract: A honing method and honing control device suitable for the honing having a large processing area is provided. The honing control device includes a grinder and an expansion member for disposition in a processing hole of a workpiece. The amount of an expanding movement when the grinder contacts the inner surface of a gauge hole via the expansion member is stored as a target expansion amount by inserting a honing head into the gauge hole having the same size as a target processing diameter of a master gauge. Then, a honing of an inner surface of the processing hole is performed by inserting the honing head within a processing hole of a workpiece moving the grinder towards an outer side of a diametrical direction by the expansion member installed within the honing head to rotate the honing head. The honing is completed when the amount of the expanding movement of the grinder reaches a target expansion amount established by the master gauge.

Abstract: A cylindrical internal surface processing method comprises forming a cylinder bore, roughening an upper section of the bore, depositing coating onto the bore, and machining a lower section of the bore and the coating. The forming of the cylinder bore includes forming the upper and lower sections with the lower section being axially spaced from the upper section and having an axial length greater than zero. The roughening creates a roughened surface such that a radially innermost edge of the roughened surface has an internal diameter smaller than an internal diameter of the lower section. The coating is deposited to cover the upper section and at least a portion of the lower section. The machining forms a tapered portion and a cylindrical portion, a radially outermost edge of the cylindrical portion having an internal diameter larger than that of a radially outermost edge of the roughened surface.

Abstract: A prespray processing method includes preparing a work surface for spray coating, roughing the work surface by pressing a tool against the work surface, having a material of the work surface displaced thereon to form a depression thereinto, and keeping the material of the work surface unremoved therefrom.

Abstract: A cylinder block has at least two cylinder banks each having cylinder bores arranged in at least two directions relative to an axis for a crankshaft. A rotator on which the cylinder block is securely disposed has a convex rounded surface. When the rotator rotates, the convex rounded surface moves along a concave rounded surface of a rotator-holding base. As a result of the rotation, the cylinder bores of the first bank or the cylinder bores of the second bank face upward in the vertical direction. Accordingly, with a single spray gun, sprayed coatings can be formed on inner surfaces of the cylinder bores of the first and second banks without having to change a mounting position of the cylinder block.

Abstract: A sprayed film forming method and apparatus in which the thickness of the sprayed film in a predetermined region is increased so as to unify the entire thickness. A sprayed film is formed at a cylinder bore inner surface while a spraying gun is moved in an axial direction during rotation inside the bore. Air inside the bore is sucked out to prevent foreign material from being caught in the sprayed film. The flow rate inside the bore tends to become higher at an axial end on a suction side, resulting in a thinned region. The supply speed of a wire serving as a spraying material to the spraying gun or the number of sprays in this region is higher than those at other portions. The thickness at the axial end of the bore is made equal while suppressing an increase in working time and spraying material used.

Abstract: An apparatus is provided to reduce the defect rate and decrease production yield by removing foreign objects even when the foreign objects are mixed in with the thermally sprayed film. The operation for forming thermally sprayed film on inner surface of cylinder bore is paused, and protrusions generated in the thermally sprayed film by foreign objects are detected by visual observation and removed by a manual operation. The thermal spraying operation is then performed until thermally sprayed film reaches the prescribed film thickness. After formation of the thermally sprayed film, a finishing operation is performed by means of honing.

Abstract: A honing method and honing control device suitable for the honing having a large processing area is provided. The honing control device includes a grinder and an expansion member for disposition in a processing hole of a workpiece. The amount of an expanding movement when the grinder contacts the inner surface of a gauge hole via the expansion member is stored as a target expansion amount by inserting a honing head into the gauge hole having the same size as a target processing diameter of a master gauge. Then, a honing of an inner surface of the processing hole is performed by inserting the honing head within a processing hole of a workpiece moving the grinder towards an outer side of a diametrical direction by the expansion member installed within the honing head to rotate the honing head. The honing is completed when the amount of the expanding movement of the grinder reaches a target expansion amount established by the master gauge.

Abstract: The adhesiveness of a thermal spray coating and a cylinder internal surface is improved by forming a sufficient roughened surface on an internal surface. A processing roller is installed on the main shaft of a processing device via a pressurizing mechanism. An uneven surface is provided on the external periphery of the processing roller. By pressing the processing roller against the internal surface while the roller rotates and moves, a fine unevenness that corresponds to the unevenness of the roller is formed on the cylinder internal surface. A thermal spray coating is formed on the internal surface where the inner surface has been roughened by forming the above-mentioned unevenness.

Abstract: A thermally sprayed coating is deposited onto a cylindrical internal surface of a base member after a rough surface has been formed on the cylindrical internal surface. The tapered surface is configured such that the internal diameter of the axial end portion is larger than the internal diameter of the remaining portions of the cylinder bore internal surface. After the tapered surface is formed, the thermally sprayed coating is honed. This method prevents exfoliation of a thermally sprayed coating at an end portion of a cylindrical internal surface in a situation where honing or another mechanical finishing process is applied to the thermally sprayed coating after the coating is formed on the cylindrical internal surface.

Abstract: A cylinder block has at least two cylinder banks each having cylinder bores arranged in at least two directions relative to an axis for a crankshaft. A rotator on which the cylinder block is securely disposed has a convex rounded surface. When the rotator rotates, the convex rounded surface moves along a concave rounded surface of a rotator-holding base. As a result of the rotation, the cylinder bores of the first bank or the cylinder bores of the second bank face upward in the vertical direction. Accordingly, with a single spray gun, sprayed coatings can be formed on inner surfaces of the cylinder bores of the first and second banks without having to change a mounting position of the cylinder block.

Abstract: A prespray processing method including preparing a work surface for spray coating, roughing the work surface by pressing a tool against the work surface, having a material of the work surface displaced thereon to form a depression thereinto, keeping the material of the work surface unremoved therefrom.