Core and method for casting cylinder head with exhaust port
AssigneeNissan Motor Co., Ltd.
InventorsYoshimasa Hayashi, Kunio Sensui
Life of this patent
Estimating the term…
Abstract
A segmented port liner is disposed about a precured inner casting core. Pre-cured casting cores are fixed onto the surface of the liner. If desired, another segmented liner may be disposed thereabout and similarly covered with the pre-cured casting cores. The above combination serves an exhaust passage casting core.
Claims9
A method of forming a cylinder head having an exhaust port passage in which a port liner is installed, comprising:
- a. preparing a cured casting core made of a moulding sand;
- b. covering said cured casting core circumferentially with a longitudinally segmented metal tube made as two semi-cylindrical segments thereby to form a first unit;
- c. covering said first unit circumferentially with a longitudinally segmented cured casting core of lesser axial length than said metal tube end made as two semi-cylindrical sand segments made of a moulding sand thereby to form a second unit;
- d. disposing said second unit in a mould;
- e. casting molten metal around said second unit in said mould in the configuration of a cylinder head thereby securing the metal tube thereto;
- and
- f. removing all the core from said second unit contained in the solidified metal forming said cylinder head.
A method of forming a cylinder head having an exhaust port passage in which double port liners are installed, comprising:
- a. covering a cured casting core made of a moulding sand with a first longitudinally segmented metal tube provided with support means thereby to form a first unit;
- b. covering said first unit with a first longitudinally segmented cured casting core made of moulding sand with said support means exposed thereby to form a second unit including the first unit;
- c. covering said second unit with a second longitudinally segmented metal tube provided with support means thereby to form a third unit including said first and second units;
- d. covering said third unit with a second longitudinally segmented cured casting core made of moulding sand with the support means thereof exposed thereby to form a fourth unit including said first, second and third units with the support means of said first and second tubes exposed;
- e. disposing said fourth unit in a mould;
- f. casting molten metal around said fourth unit in said mould in the configuration of a cylinder head thereby fixing both metal tubes thereto, and
- g. removing all core parts from said fourth unit contained in the solidified metal forming said cylinder head.
A method of forming a cylinder head having an elongated markedly curved exhaust port passage in which a port liner is installed, comprising:
- a. preparing a longitudinally curved cured casting core;
- b. covering said cured casting core circumferentially with a longitudinally segmented metal tube made of semi-cylindrical segments thereby to form a first unit, said metal tube being longitudinally curved to accommodate said cured casting core internally thereof and having at least one lug from each segment extending radially outwardly;
- c. covering said first unit with a longitudinally segment cured casting core made of semi-cylindrical sand segments to substantially wrap the same circumferentially thereby to form a second unit, a leading end of each said lug being disposed projecting outwardly laterally from said second unit;
- d. disposing said second unit in a mould;
- e. casting molten metal around said second unit in said mould in the configuration of a cylinder head;
- and
- f. removing said cores from said second unit leaving each said lug contained in the solidified metal which forms said cylinder head.
A core unit for use in casting a cylinder head of an internal combustion engine having, an exhaust port passage with a port liner installed therein, the core unit comprising a solidified and pre-cured rigid sand unitary core made of a moulding sand, the core being curved and configured longitudinally in a configuration to correspond to an exhaust port passage in a cylinder head to be cast, a curved metal tube circumferentially intimately enclosing the sand core and corresponding longitudinally with only an axial length of the sand core therein, said tube consisting of independently pre-fabricated semi-cylindrical metal segments fixed relative to each other subsequent of enclosing of said sand core therein;
- means on said metal segments for fixing them together permanently defining said tube circumferentially of said sand core, a plurality of semi-cylindrical pre-cured moulding sand segments made of moulding sand adhered on said tube covering it circumferentially and extending along only a certain axial length of said tube, and said tube with said fixing means exposed constituting in use an exhaust port passage liner with a cylinder head cast thereabout embedding said fixing means therein.
Dependencies are inferred from the claim text.