Abstract
A slide for the high pressure die casting of at least one closed deck engine block having at least one cylinder is disclosed. The slide includes a tool steel portion with reliefs for forming a water jacket surrounding each cylinder. At least one expendable core is located in each relief, the expendable core having an inner surface and an outer surface with an aperture extending therethrough. The outer surface and inner surface of the expendable core is coextensive with an inner surface and outer surface of the tool steel portion. A method for high pressure die casting a closed deck engine block using the disclosed slide and expendable cores is also disclosed. The expendable cores are separable from the reliefs in the slide, and form bridges or supports across a water jacket to add stiffness and rigidity to the cast engine cylinders.
Claims
1. An expendable core for use in high pressure die casting a closed deck engine block, the core comprising an arcuate inner surface, an arcuate outer surface, an upper portion, a lower portion, a top surface and a bottom surface, a first side surface and a second side surface, and an aperture extending through the core from the inner surface to the outer surface in a horizontal direction through the upper portion; wherein the entire lower portion has a thickness greater than the upper portion, the difference in thickness defining a shelf portion, wherein the thickness of the lower portion is consistent from the shelf portion to the bottom surface, wherein the first side surface and the second side surface taper outwardly from the inner surface and intersect with the outer surface, and wherein the aperture is located above the shelf portion and is parallel to a top surface of the shelf portion.
2. The expendable core of claim 1 wherein the outer surfaces of the upper portion and the lower portion are arcuate with the same radius of curvature.
3. The expendable core of claim 1 wherein the first and second side surfaces are outwardly tapering surfaces from the inner surfaces that intersect with the outer surfaces of the upper portion and the lower portion, and wherein the outwardly tapering first and second side surfaces of the lower portion have a greater thickness that the outwardly tapering side surfaces of the upper portion.
4. The expendable core of claim 3 wherein the inner surface of the lower portion includes a central concave surface.
5. The expendable core of claim 1 wherein the expendable core is constructed of salt.
6. The expendable core of claim 1 wherein the expendable core is constructed of bonded sand.
7. The expendable core of claim 6 wherein the bonded sand is resin bonded green sand.
8. The expendable core of claim 6 wherein the bonded sand is resin bonded dry sand.
9. The expendable core of claim 1 wherein the expendable core is constructed of semi-permanent steel inserts.
10. The expendable core of claim 1 wherein the expendable core is constructed of a material having a melting point less than aluminum.
11. The expendable core of claim 10 wherein the expendable core is constructed of a metal.
12. The expendable core of claim 11 wherein the metal is selected from tin, zinc or an alloy thereof.
13. The expendable core of claim 1 wherein the expendable core is constructed of a material having a melting point less than the eutectic temperature of aluminum-silicon alloys.
14. The expendable core of claim 13 wherein the expendable core is constructed of a metal.
15. The expendable core of claim 14, wherein the metal is selected from tin, zinc or an alloy thereof.
16. The expendable core of claim 1 wherein the expendable core is constructed of plaster.
17. The expendable core of claim 1 wherein the outwardly tapering first and second side surfaces of the lower portion have a greater thickness than the outwardly tapering side surfaces of the upper portion.
18. The expendable core of claim 17 wherein the expendable core is constructed of a material having a melting point less than aluminum.
19. The expendable core of claim 17 wherein the expendable core is constructed of plaster, tin, zinc or an alloy of tin or zinc.
20. The expendable core of claim 1 wherein the inner surface of the lower portion includes a central concave surface.
21. The expendable core of claim 20 wherein the expendable core is constructed of a material having a melting point less than aluminum.
22. The expendable core of claim 20 wherein the expendable core is constructed of plaster, tin, zinc or an alloy of tin or zinc.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a perspective view of a cylinder bore and water jacket slide for the high pressure die casting of at least one closed deck engine cylinder, with expendable cores inserted into the slide.
(2) FIG. 2A is a section view of the cylinder bore and water jacket slide if FIG. 1 taken along line A-A′.
(3) FIG. 2B is a section view similar to FIG. 2A, but demonstrating only one inserted expendable core.
(4) FIG. 3 is a perspective view of a cylinder bore and water jacket slide for the high pressure die casting of at least one closed deck engine cylinder, with expendable cores removed to demonstrate reliefs in the tool steel portion.
(5) FIG. 4A is a section view of the cylinder bore and water jacket slide if FIG. 1 taken along line B-B′.
(6) FIG. 4B is a section view similar to FIG. 4A, but demonstrating only one tool steel relief.
(7) FIG. 5 is a perspective view of an expendable core in accordance with an embodiment of the present application.
(8) FIG. 6 is a front view of the expendable core of FIG. 5.
(9) FIG. 7 is a rear view of the expendable core of FIG. 5.
(10) FIG. 8 is a side view of the expendable core of FIG. 5.
(11) FIG. 9 is a top view of the expendable core of FIG. 5
(12) FIG. 10 is a perspective view of a closed deck engine head deck formed using the slide, expendable cores and methods of the present application.
(13) FIG. 11 is a top view of a closed deck engine head deck formed using the slide, expendable cores and methods of the present application.
(14) FIG. 12 is a section view of a closed deck engine head deck formed using the slide, expendable cores and methods of the present application taken along line C-C′ of FIGS. 10 and 11.
DETAILED DESCRIPTION OF THE DRAWINGS
(15) Referring first to FIGS. 1, 10 and 11, the present application is directed to a cylinder bore and water jacket slide 10 for the high pressure die casting of at least one closed deck engine head deck 12 having at least one cylinder 14. The slide 10 includes at least one mandrel 20 that receives a cast in place cylinder bore liner 22 for forming each engine cylinder. While the figures depict a closed engine head deck 12 having one cylinder 14, those of ordinary skill in the art will understand that the present invention may apply to an engine head deck having a plurality of cylinders 14, including, but not limited to, two cylinder closed deck engine head decks, four cylinder closed deck engine head decks, six cylinder closed deck engine head decks, whether in-line or of a V configuration.
(16) Referring now to FIGS. 1 through 4B, the cylinder bore and water jacket slide 10 includes a tool steel portion 24. The tool steel portion 24 is used to partially form a water jacket 26 that surrounds each cylinder 14 to aid in cooling the cylinder during engine operation. The tool steel portion 24 includes an inner surface 34 and an outer surface 36.
(17) Referring now to FIGS. 3, 4A and 4B, the tool steel portion 24 includes at least one relief 28. Preferably, the cylinder bore and water jacket slide 10 includes a plurality of tool steel reliefs 28. The tool steel reliefs 28 have an inner relief surface 30 and a side surface 32. The relief 28 further includes a bottom surface 38 and a second side surface 40.
(18) At least one, and preferably a plurality of expendable cores 50, as shown in FIGS. 1, 2A and 2B are located in the reliefs 28. Referring now to FIGS. 5-9, the expendable cores 50 have an inner surface 52 and an outer surface 54. An aperture 56 extends through the inner surface 52 to the outer surface 54. The aperture 56 may vary in circumference. As shown in FIGS. 1, 2A and 2B, when the expendable core 50 is located in the tool steel relief 28, the outer surface 54 of the expendable core 50 is coextensive with the outer surface 36 of the tool steel portion 24. Likewise, the inner surface 52 of the expendable core 50 is coextensive with the outer surface 54 of the tool steel portion 24.
(19) Referring again to FIGS. 2A and 2B, the tool steel portion 24 includes an upper portion 25 and a lower portion 27, Likewise, the expendable core 50 has an upper portion 58 and a lower portion 60, as shown in FIGS. 5-9. The lower portion 60 of the expendable core 50 has a greater thickness than the upper portion 58. The difference in thickness between the upper portion 58 and the lower portion 60 defines a shelf 62. In one embodiment of the present application, the aperture 56 is located in the upper portion 58 of the expendable core 50. The expendable cores 50 also include a first side surface 63 and a second side surface 64. The expendable cores 50 further include a bottom surface 66 and a top surface 68.
(20) As shown in FIGS. 1, 2A and 2B, with reference to FIGS. 3, 4A and 4B, a lower portion of the inner surface 52 of the expendable core 50 engages the inner surface 34 of the tool steel portion 24 when the expendable core 50 is inserted into the relief 28. Likewise, when the expendable core 50 is placed in the relief 28, the bottom surface 66 of the core 50 engages the bottom surface 38 of the relief 28 and the tool steel portion 24. Likewise, the first side surface 63 of the core 50 will engage the first side surface 32 of the relief 28 of the tool steel portion 24, and the second side surface 64 of the core 50 will engage the second side surface of the relief 28 of the tool steel portion 24. The expendable core 50 is placed in the relief 28 such that the tool steel portion 24, including the relief 28, is separable from the expendable core 50 after high pressure die casting of at least one closed deck engine cylinder block.
(21) As shown in FIGS. 5-9, the outer surface 54 of the expendable core 50 is arcuate. Likewise, the inner surface 52 of the expendable core 50 is also arcuate. Despite the fact that the lower portion 60 of the expendable core 50 has a greater thickness, the radius center of the outer surface 54 on both the upper portion 58 and the lower portion 60 are the same. The first side surface 63 and the second side surface 64 of the expendable core 50 taper outwardly from the inner surface 52 and intersect with the outer surface 54. Notably, the outwardly tapering first and second side surfaces of the lower portion 60 have a greater thickness than the outwardly tapering side surfaces of the upper portion 58. In one embodiment, the inner surface 52 of the lower portion 60 includes a central concave surface 70. The expendable cores 50 may be manufactured by methods known by those having ordinary skill in the art. The expendable cores 50 may be salt cores manufactured in accordance with U.S. Pat. No. 9,527,131; the entirety of which is incorporated herein by reference. Alternatively, the expendable cores 50 may be constructed of bonded sand, such as a resin bonded sand, green sand or dry sand. Further alternatively, the expendable cores 50 may be constructed of semi-permanent metal inserts that are mechanically removed after casting. In one embodiment, the metal inserts may be selected from steel, tin or zinc. Still further, the expendable cores 50 may be constructed of plaster, wax, foam or other melt-able or dissolvable materials. In certain embodiments, the expendable cores 50 may be selected from a material that has a lower melting point than aluminum at 660° C., or from a material having a melting point less than the eutectic temperature of aluminum-silicon alloys at 577±1° C. Specifically, such melt-able expendable cores 50 may be advantageously constructed of a metal such as tin or zinc or alloys thereof.
(22) Referring now to FIGS. 10, 11 and 12, the present application further contemplates a method for high pressure die casting of a closed deck engine block 12. The method contemplates placing the slide of FIG. 1 in a high pressure die casting mold for an engine block. The slide 10 has at least one mandrel 20 that locates a cast in place cylinder bore liner 22. The slide 10 further includes a tool steel portion 24 for forming at least one cylinder 14 surrounding the cast in place cylinder bore liner 22 and a water jacket 26 surrounding each cylinder 14. The tool steel portion 24, as previously described, includes at least one relief 28, the relief having an inner surface 30 defining a tool steel relief 28. The method contemplates inserting at least one expendable core 50 into the tool steel relief 28, the core 50 having an inner surface 52, and outer surface 54, and an aperture 56 extending through the inner surface 52 to the outer surface 54. The method contemplates placing a cast in place cylinder bore liner 22 over each mandrel 20, closing the high pressure die casting die, and injecting a molten aluminum silicon alloy into the die to create a closed deck engine block casting 12 having at least one cylinder 14 with a cast in place cylinder bore liner 22 and a water jacket 26 surrounding the cylinder 14. The water jacket 26 has an inner wall 72 and an outer wall 74, the inner wall 72 corresponding to an outer wall of the cast cylinder 14. During the step of injecting a molten aluminum alloy into the die, the molten aluminum silicon alloy enters the aperture 56 of the core 50 and, upon solidification, creates a bridge 80 between the inner wall 72 and the outer wall 74 of the water jacket 26. The closed deck engine block in casting is then cooled and the cylinder bore and water jacket slide are removed from the high pressure die casting mold and the closed deck engine block casting. When the slide 10 is removed, the core will remain with the closed deck engine block casting and be removed from the relief 28 of the tool steel portion 24 of the slide 10. After the closed deck engine Hock casting 12 is completely cooled, the core may be dissolved, revealing the closed deck engine block support or bridge 80. As noted, a support extends between the inner wall 72 and the outer wall 74 of the water jacket 26 and adds rigidity to each cast cylinder 14.
(23) It must be noted that the present invention may include a casting of a closed deck engine block having multiple cylinders, including but not limited to, two, four and six cylinders in either a linear or V shape configuration. Likewise, the slide 10 may include a plurality of reliefs 28, and a plurality of cores 50 such that a plurality of supports 80 may be located along the circumference of the water jacket 26 and cylinder 14. The aperture 56 in the core 50 may vary in size, and as shown in FIGS. 10-12, cores 50 having different sized apertures 56 may be used in a slide 10 to create bridges or supports 80 of different sizes. The inventors contemplate that one bridge or support 80 will add stiffness and rigidity to the cylinder 14. However, the inventors contemplate having multiple supports 80 per cylinder, preferably two supports 80, more preferably four support 80 per cylinder, and most preferably six or more supports 80 per cylinder.
(24) In the method of the present application, the step of inserting an expendable core 50 into a relief 28 may include a step of inserting a plurality of expendable cores 50 into a plurality of reliefs 28. As noted, the cores 50 have an upper portion 58 and a lower portion 60, with the lower portion 60 having a greater thickness than the upper portion 58, the difference in thickness defining a shelf 62. When one or more expendable cores 50 are inserted into one or more reliefs 28 of the tool steel portion 24 of the slide 10, each expendable core 50 is positioned in a relief 28 such that the inner surface 52 of the lower portion 60 of each expendable core 50 engages the lower inner surface 30 of the tool steel relief 28. Similarly, the bottom surface 66 of each core 50 will engage a bottom surface 38 of the tool steel relief 28, and the first and second side surfaces of each expendable core will engage the first and second side surfaces of the tool steel reliefs 28. After placement of one or more cores in one or more reliefs 28, the top portion 58, including the aperture 56, are exposed to the molten aluminum silicon alloy when the alloy is injected into the high pressure die casting mold.
(25) The step of placing a cast in place cylinder bore liner 22 over each mandrel 20 may further include placing a cylinder bore liner 22 having a top surface 82 over each mandrel 20, the top surface 82 of the cylinder bore liner 22 abutting each shelf 62 of each inserted expendable core 50.
(26) In the present disclosure, certain terms have been used for brevity, clearness and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatuses described herein may be used alone or in combination with other apparatuses. Various equivalents, alternatives and modifications are possible within the scope of the appended claims. Each limitation in the appended claims is intended to invoke interpretation under 35 U.S.C. § 112, sixth paragraph only if the terms “means for” or “step for” are explicitly recited in the respective limitation.
