Cylinder block and cylinder sleeve, method of producing cylinder block and cylinder sleeve by friction stir welding, and friction stir welding method

A cylinder sleeve for being inserted in a cylinder bore defined in a block body of a cylinder block for an internal combustion engine, said cylinder bore having therein a first annular recess and a second annular recess and having projecting walls, said cylinder bore communicating with a water jacket, comprising:

• a hollow cylindrical body;
• a larger-diameter portion projecting diametrally outwardly from an outer circumferential wall of said hollow cylindrical body, and closing an end of said water jacket at a gasket surface;
• and
• a step disposed on an outer circumferential wall of said larger-diameter portion
• wherein said larger-diameter portions of said adjacent cylinder sleeves are stacked through said step.

A cylinder sleeve for being inserted in a cylinder bore defined in a block body of a cylinder block for an internal combustion engine, said cylinder bore having therein a first annular recess and a second annular recess and having projecting walls, said cylinder bore communicating with a water jacket, comprising:

• a hollow cylindrical body;
• a reduced-diameter portion provided by reducing a diameter of an inner circumferential wall of said hollow cylindrical body;
• and
• a larger-diameter portion projecting diametrally outwardly from an outer circumferential wall of said hollow cylindrical body.

A friction stir welding method of joining an inner wall of an insertion hole-defined in a first member and an outer wall of a hollow second member inserted in said insertion hole, by friction stir welding, comprising the steps of

• providing, on an inner wall of said second member, a reduced-width portion having a tapered surface which is progressively reduced in width away from an open end of said insertion hole;
• bringing a probe of a friction stir welding tool into abutment against said tapered surface, and thereafter moving said friction stir welding tool along said tapered surface;
• softening and stirring each material of said tapered surface and an outer wall of said second member and the material of an inner wall of said insertion hole in said first member, with friction heat produced when said probe is rotated, thereby friction-stir-welding said materials;
• and
• removing said probe from said tapered surface, and thereafter removing said reduced-width portion.

A friction stir welding method comprising the steps of:

• embedding a friction stir welding tool which is rotating into a cylinder block having an abutting region;
• moving at least one of said friction stir welding tool and said cylinder block to displace said friction stir welding tool along said abutting region for softening the material of said abutting region with frictional heat and stirring the material of said abutting region with said friction stir welding tool to join said material of said abutting region;
• and
• removing said friction stir welding tool from a gasket surface of said cylinder block after said material of said abutting region is joined;
• wherein a removal hole formed by removing at least said friction stir welding tool is machined into a stud bolt hole.

A friction stir welding method comprising:

• embedding a friction stir welding tool which is rotating into a cylinder block having an abutting region;
• moving at least one of said friction stir welding tool and said cylinder block to displace said friction stir welding tool along said abutting region for softening the material of said abutting region with frictional heat and stirring the material of said abutting region with said friction stir welding tool to join said material of said abutting region;
• and
• removing said friction stir welding tool from a gasket surface of said cylinder block after said material of said abutting region is joined;
• wherein a removal hole formed by removing at least said friction stir welding tool is machined into an oil hole, a knock hole, or a dowel pin hole.

A friction stir welding method of friction-stir-welding an abutting region of a block body and a cylinder sleeve inserted in a cylinder bore in said block body, with a friction stir welding tool which is rotating, thereby producing a cylinder block, comprising the steps of:

• embedding said friction stir welding tool into at least one of said block body and said cylinder sleeve;
• displacing said friction stir welding tool along said abutting region for softening the material of said abutting region with frictional heat and stirring said material of said abutting region with said friction stir welding tool to join said abutting region;
• and
• removing said friction stir welding tool from said abutting region or said cylinder sleeve-after said abutting region is joined;
• wherein said friction stir welding tool is removed from a region in which a water passage is to be formed in communication-with a water jacket between said block body and said cylinder sleeve.

A method of manufacturing a cylinder block by friction-stir-welding a block body having a cylinder bore and a cylinder sleeve inserted in said cylinder bore, comprising the steps of:

• embedding a friction stir welding tool which is rotating into said cylinder sleeve from an inner circumferential wall thereof until said friction stir welding tool reaches an inner circumferential wall of said cylinder bore;
• moving said friction stir welding tool to soften the material of said cylinder sleeve and the material of said block body with frictional heat and stir said materials with said friction stir welding tool, thereby joining said cylinder sleeve and said block body to each other;
• and
• removing said friction stir welding tool after said cylinder sleeve and said block body are joined to each other;
• wherein said friction stir welding tool is removed from said cylinder sleeve at a position below a bottom dead center of a piston ring fitted over a circumferential side wall of a piston inserted in said cylinder bore.

A method of manufacturing a cylinder block by friction-stir-welding a block body having a cylinder bore having a diametrally dented step and a friction stir welding tool removal member mounted on a gasket surface, and a cylinder sleeve inserted in said cylinder bore, comprising the steps of:

• embedding a friction stir welding tool which is rotating into said cylinder sleeve from an inner circumferential wall thereof until said friction stir welding tool reaches an inner circumferential wall of said cylinder bore;
• moving said friction stir welding tool to soften the material of said cylinder sleeve and the material of said block body with frictional heat and stir said materials with said friction stir welding tool, thereby joining said cylinder sleeve and said block body to each other;
• and
• removing said friction stir welding tool after said cylinder sleeve and said block body are joined to each other;
• wherein said friction stir welding tool is removed from said friction stir welding tool removal member after said friction stir welding tool is moved from said inner circumferential wall of said cylinder sleeve to said friction stir welding tool removal member.

Method of manufacturing a closed-deck cylinder block in which a water jacket is formed in a clearance between a block body and a cylinder sleeve, and an end of said water jacket at a gasket surface is closed, comprising the steps of:

• producing a block body having a cylinder bore having a diametrally dented step and a placement area for placing an end face of said cylinder sleeve thereon;
• inserting said cylinder sleeve into said cylinder bore, placing said end face of said cylinder sleeve on said placement area, and forming said water jacket between an outer circumferential wall of said cylinder sleeve and said step;
• and
• friction-stir-welding said cylinder sleeve and an inner circumferential wall of said cylinder bore to produce a cylinder block.