US2820267A

US2820267A - Cylinder head coring

Info

Publication number: US2820267A
Application number: US398805A
Authority: US
Inventors: Clayton B Leach
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1953-12-17
Filing date: 1953-12-17
Publication date: 1958-01-21
Anticipated expiration: 1975-01-21

Description

Jan. 21; I958 I c, c v 2,820,267 I CYLINDER HEAD CURING I Filed Dec. 17, 1953 5.Sheets-Sheet l Inventor agz zemmzwg r' gww Attorney c. B. LEACH CYLINDER HEAD CORING 5 Sheet-Sheet 2 Fil ed Dec. 17, 1953 Inventor 622 2612 26.5222

Attorneys Jan. 21, 1958 c. B. LEACH' CYLINDER HEAD CORING Filed Dec; 17, 1955 5 Sheets-Sheet 3 Inventor feat/Q Attorneys Jan. 21, 1958 c. B. LEACH CYLINDER HEAD CORING 5 Sheets-Sheet 4 Filed Dec. 17 1953- United States Patent 9 CYLINDER HEAD CURING Clayton B. Leach, Pontiac, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 17, 1953, Serial No. 398,805

13 Claims. (Cl. 22-131) This invention relates to internal combustion engine coring and particularly to a cylinder head coring arrangement for overhead valve engines in which only a very few cores are used, sub-assembly of the core is eliminated, and handling of the cores is reduced to a minimum.

Heretofore conventional coring arrangements and methods of assembling engine cores have required the forming, handling and assembling of a multiplicity of cores to form a coring assembly for a cylinder head. For example, eight-cylinder V-type internal combustion engines have conventionally required approximately eight cores for each cylinder head, a total of sixteen cores per engine, while eight-cylinder in-line over-head valve engines normally have necessitated the use of about eleven cylinder head cores per engine. A comparatively large amount of core sand and binder must also be used with these coring assemblies.

Moreover, these conventional coring arrangements and the processes for assembling them require sub-assembly and pasting of the cores. Each of these many cores is subject to some breakage due to handling, of course; and whenever water jacket cores are pasted together, as is conventionally done, there are numerous instances in which thin fins of metal remain. When these fins protrude into water jacket passages, they tend to restrict water circulation and interfere with the proper operation of the engine. Removal of such metal flashing necessitates the use of increased machining operations, thus adding to the cost of the engine.

A principal object of the present invention, therefore, is to provide a cylinder head coring arrangement and method for assembling the cores in which the number of cores required per head is greatly decreased, sub-assembly, nailing and pasting of the cores are eliminated, and the amount of core sand and binder required is substantially reduced. These factors result in lower foundry costs, savings being efiected both in materials and personnel. A further object of this invention is to provide a mold and coring assembly which forms a sounder cylinder head casting due to the effective use of green sand in the mold as a substitute for large slab cores. Since practically the entire outside surface of the casting is surrounded by green sand during pouring, the quality of the casting is improved due to the high porosity of the green sand as compared with baked core materials.

The above and other objects are attained in accordance with the present invention by a cylinder head coring assembly in which a single water jacket core replaces the two water jacket core halves previously used and which required pasting together. This invention also employs a single exhaust port core and a single intake port core rather than the five separate port cores heretofore used. Moreover, the present arrangement eliminates the conventional large base slab core and instead uses the green molding sand in the drag half of the flask to full advantage, thereby further reducing operating costs.

Other objects and advantages of this invention will more fully appear from the following detailed description of a preferred embodiment of the invention shown in the accompanying drawings, in which:

Figure 1 is a perspective view showing the cores employed in a conventional coring arrangement for casting a cylinder head of a V-8 internal combustion engine;

Figure 2 is a perspective view showing the four cores used in accordance with the present invention to form a V-8 engine cylinder head;

Figure 2a is a perspective view of a modification of the intake port water jacket core shown in Figure 2;

Figure 3 is a perspective view showing the relative positions of the water jacket core loose piece, the intake port core, and the main water jacket core after the initial assembly steps;

Figure 4 is a perspective view of the completed core assembly after the exhaust port core has been placed in position;

Figure 5 is a partially schematic, phantom end view, with parts broken away and in section, of an eight-cylinder V-type gasoline engine showing a cylinder head formed by a coring assembly in accordance with the present invention;

Figure 6 is a fragmentary sectional View of a cylinder head of the V-8 engine shown in Figure 5;

Figure 7 is a sectional view of the green sand mold and cores used to form the cylinder head cavities and walls along the line 7-7 of Figure 6; and

Figure 8 is a sectional view of the green sand mold and cores used to form the cylinder head cavities and walls along the line 3tl of Figure 6.

Referring more particularly to the drawings, in Figure 1 is shown the relatively complicated coring system heretofore conventionally used in casting cylinder heads for V-S engines. It will be noted that this arrangement consists of a multiplicity of cores, including a large base slab core 1%), two Water jacket cores 12 and 14, and a plurality of port cores 16, 18, 20, 22 and 24.

in assembling these cores, the various port cores and water jacket cores are all positioned on the base slab core 10. This slab core forms the depressions required in the bottom wall of the cylinder head for the combustion chambers and cooling water ports. More specifically, the lower water jacket core 12 is placed on the base slab core and pasted thereto with the laterally extending pro jections 26 and 28 of the lower water jacket core resting in slots 30 and 32 in the inner Wall of the slab core. The port cores 16, 18, 20, 22 and 24 are then seated in their respective positions on the lower water jacket core 12 and the base slab core 10, as is well known in the art.

When these ports cores are properly located in the mold, port cores to and 18 extend through slots 34 and 36 in the outer wall of the slab core, their port-defining ends 38 and 40 extending into the openings 42 and 44, respectively, in the lower water jacket core near the ends thereof. Likewise, port cores 20 and 24 are located so that their outer ends 46 and 48 are fitted into slots 50 and 52, respectively, in the inner wall of the slab core, while their inner ends 54 and 56 extend into the recesses 58 and 60, respectively, formed in the lower water jacket core. In a similar manner, port core 22 is positioned so that one end 62 rests in a slot 64 in the inner wall of the base slab core and its other end 66 is seated in another slot 68 in the opposite wall of the slab core. The arm portions 74) and 72 extend into transverse recesses 74 and 76, respectively, near the center of the lower water jacket core. Each of the port cores is pasted to the wall of the base slab core on which it is supported.

Following the proper positioning of the port cores on the lower water jacket core 12 and the base slab core 10, the upper water jacket core 14 is placed over the port cores and the lower water jacket core 12 so that the laterally seamed? extending projections 78 and 80 rest on top of the projections 26 and 28 of the lower water jacket core. The two water jacket cores are then pasted and/or nailed together in this position with the port cores 16, 18, 2h, 22 and 24 located between them. Core print projections or core locators 82, which extent longitudinally from the ends of the upper water jacket core, seat in mating core prints 84 in the end walls of the base slab core and aid in providing proper spatial separation of the water jacket cores relative to the base slab core and port cores. Rather than following the exact procedure described above, the port cores first can be assembled between the water jacket cores, the latter next pasted and nailed together, and the resultant sub-assembly then pasted in position in the base slab core. However, this alternative method is normally more diflicult and, unless great care is exercised in placing the sub-assembly on the slab core, edges of the port cores may be broken or chipped.

After all of the cores are thus located on the base slab core 1% the resultant core assembly is positioned on the green sand in the drag half of the mold. If desired, transfer of the core assembly to the mold may be accomplished by means of a core transfer fixture.

When the above-described conventional coring arrangement for a cylinder head of an overhead valve V-8 gasoline engine is compared with the four cores which constitute the coring assembly in accordance with the present invention, the advantages of the latter with respect to number of cores, ease of assembly, cost, etc., are apparent. As shown in Figure 2, the new and improved coring arrangement includes an exhaust port core 90, a main water jacket core 92, an intake port core 94, and an exhaust port water jacket core or water jacket core loose piece 96. For purposes of clarification, this latter core and the intake port core 94 are also shown with broken lines in unassembled position in Figure 2.

Referring to Figures 2 through 4, these cores are preferably assembled in the following manner. First the water jacket core loose piece 96 is placed in proper position on the green sand in the drag half of the mold. The intake port core 94 is next assembled in the mold by placing the two central exhaust port-defining arm portions 98 and 100 of the core around the upstanding projection 101 and into the recesses 102 provided in the upper surface of the water jacket core loose piece 96. When the intake port core is so positioned, the surfaces of the arm portions 98 and 100 are spatially separated from the surfaces of the loose piece 96. This arrangement is shown by the solid line sub-assembly in Figure 2. Other portions of the intake port core rest on the green sand in the drag, as will be hereinafter explained in greater detail.

The main water jacket core 92 is then placed in position over the laterally extending arm portions of the intake port core 94, as shown in Figure 3, with the inturned longitudinally extending side projections 104 contacting the end surfaces 108 of the longitudinal bar portion 110 of the intake port core. The projections 104 serve as core locators which rest in core prints in the green sand of the drag half of the mold and aid in locating the main water jacket core relative to the green sand as well as maintaining the intake port core 94 in proper longitudinal position with respect to the water jacket core 92, the loose piece 96, and the green sand.

Longitudinally extending core print projections or core locators 111 on the ends of the main water jacket core engage corresponding core prints or depressions formed in the green sand of the drag half of the mold. This engagement assists in maintaining the proper spatial separation between the main water jacket core and the green sand and other cores. Similarly, depending core print projections or core locators, not shown, are provided on the bottoms of the water jacket core 92 and the loose piece 96 and engage appropriate core prints in the green sand mold in the drag, thus properly locating these cores relat veto the mold.

Finally, the exhaust port core is fitted into the main Water jacket core 92 in the manner shown in Figure 4, with the end exhaust port-defining arm portions 112 and 114 and the inner exhaust port-defining arm portions 116 and 118 extending into the openings 121i), 122, 124 and 126, respectively, in the adjacent side of the Water jacket core. Since these ann portions are somewhat curved, this may be accomplished by rocking the exhaust port core into position with. an arcuate or curvilinear movement. On the other hand, if the aforementioned curvature of the

arm portions

112, 114, 116 and 118 is only slight, these arm portions may be inserted into the

openings

120, 122, 124 and 126 by mere translational movement of the exhaust port core 90.

After the cores are assembled in the above manner on the green sand in the drag, the cope half of the mold is placed in position over the drag and assembled cores. The resultant arrangement, which is shown in Figures 7 and 8, hereinafter will be described in greater detail.

In the embodiment of the invention shown in the drawings, the intake port core 94 helps form the two central exhaust bores or ports as well as the four intake ports, and aids in forming one side contour of the cylinder head casting. The exhaust port core 90 forms part of the opposite side contour of the casting, the two outer exhaust bores, and part of the two central exhaust bores. H desired, the latter core may be provided with laterally and/ or vertically extended end wall portions for manufacturing purposes. The combustion chambers, spark plug pockets, rocker arm pockets, and the remainder of the outside contour are formed by the green sand of the mold.

It will be understood, of course, that the above-outlined procedure for assembling the cores can be altered somewhat and the coring arrangement handled in a core transfer or assembly fixture. Thus, the various cores can be assembled in a similar manner within a conventional type of core transfer fixture which is adapted to properly handle these particular cores. This fixture and the assembled cores can then be transported to the drag half of the green sand mold, and the fixture removed to deposit the core assembly in position in the mold. Moreover, these cores may be designed to be assembled in the reverse manner, if desired, and the molten casting metal can then be poured around the cores while the latter are in what normally might be considered an inverted position.

As indicated above, the water jacket core 92 performs the functions of the two water jacket cores heretofore used. It will be appreciated, therefore, that the use of a unitary main water jacket core not only reduces the number of cores, but it also simplifies assembly of the cores and eliminates the necessity for wiring, nailing or pasting cores together into a sub-assembly. As a result, there is a considerable saving in the required floor space, personnel and time. Since pasting is eliminated, grinding operations to provide perfectly flat mating surfaces are likewise unnecessary. Moreover, the two mating water jacket cores previously used tended to separate upon pour ing, resulting in the formation of fins. The present coring arrangement, on the other hand, substantially reduces the problem of finning and its attendant difiiculties.

It will be noted that the four exhaust port-defining

arm portions

112, 114, 116 and 118 of exhaust port core 90 are rigidly interconnected by a relatively heavy supporting bar portion 130. In this manner two of the separate port cores previously used and a portion of a third port core are combined into a single core. Similarly, the intake port core 94 is provided with four intake

portdefining arm sections

132, 134, 136 and 138, as well as the pair of centrally located exhaust port-defining arm portions 98 and 100, all of which are supported by the longitudinally extending supporting portion 110. Such an arrangement combines in this single intake port core the two intake port cores heretofore used and half of the third exhaust port core previously necessary.

The supporting or connecting bar portions 130 and ,5 of the exhaust port core 90 and the intake port core 94, respectively, retain their respective port-defining arm portions in proper alignment. Accordingly, if the core prints in the green sand mold are formed with sufiicient precision, it is possible to eliminate part or all of the supporting bar portions 13d) and 110 and to use instead separate small port cores. Such an arrangement would make the use of an assembling fixture even more desirable than if only the two cores are used. However, the elimination of the relatively small amount of core sand and binder required to form the supporting

portions

130 and 110 normally does not warrant the use of separate cores in view of the greater assembly and alignment problems which attend the latter arrangement.

It is unnecessary to use the water jacket core loose piece 96 if crossover heat is not employed, and hence this core usually would not be included in a coring arrangement for the cylinder head of an in-line engine. Moreover, the water jacket core loose piece may be used in the form of the intake port water jacket core 140 shown in Figure 2a. If a core of this form is employed in place of the loose piece 96, the port-defining

arms

132 and 134 of the intake port core 94 are positioned above and extend into recesses or grooves 142 and 144, respectively, of the core 140 near one end thereof, while the portdefining

arms

136 and 138 likewise are located above and extend into the opposite end recesses 146 and 148, respectively. As when the water jacket loose piece 96 is used, the central port-defining arms 98 and 1% of the intake port core 94 cooperate in a similar manner with the grooves 150 and 152 in the central portion of the intake port water jacket core 140. When the intake port core is thus assembled over core 140, each pair of arms is separated by an upstanding projection 154 on the core 141'). In each instance, the port-defining arms are spatially separated from all surfaces of the intake port water jacket core.

Of course, if it is desired to form water jackets adjacent the intake ports while eliminating crossover heat, it is not necessary to form the recesses or grooves 150 and 152 in the intake port water jacket core 140. Likewise, if crossover heat is not used and water jackets are not to be formed under the intake ports, the entire core 140 may be omitted.

Referring now to Figures 7 and 8, which show the final cylinder head mold and coring assembly immediately before pouring the molten casting metal, it will be observed that the intake port core 94 and the exhaust port core 90 are supported in the green sand 156 in the drag half of the flask primarily at their longitudinally extending supporting bar portions 110 and 139, respectively. However, the green sand in the drag also supports the ends of the port-defining arm portions, such as portions 98 and 116 of the

cores

94 and 90, respectively, shown in Figure 7. Thus it can be seen that the end of the port-defining arm portion 98 of the core 94 is supported by the upstanding projection 158 in the green sand 156 of the drag half of the mold. The end of the core-defining arm portion 116 of core 90 in turn is supported on the upper surface of arm 98.

These cores are maintained in proper position laterally by means of the mating contours of the free ends of arms 98 and 116 and the depending ridges or

projections

160 and 162 on the

bar portions

110 and 130, respectively, of the cores 94 and 99. The ridges 169 and 162 engage corresponding recesses in the green sand 156 of the drag half of the mold and thereby function as core locators. As shown in Figures 7 and 8, the green sand 164 of the cope half of the mold similarly engages the top and side surfaces of the reinforcing or supporting bars 116) and I 130. These bars preferably have their outer side surfaces sloping slightly inwardly from the mold parting line 166 "in order to facilitate positioning of the intake and exhaust port cores in the drag half of the mold and to prevent attrition between these cores and the green sand of the cope half when the the latter is lowered into position over the cores. i

As can be seen from Figure 8, the port-defining arm portion 132 of core 94 is likewise supported atits free inner end by the upwardly extending projection 168 formed in the green sand in the drag. The broken lines in Figure 8 indicate the location of walls in the cylinder head casting formed by the water jacket core 92 and the exhaust port core 90, thereby indicating the extent and function of arm 112 of the latter core.

Thus it will be noted that the intake port core 94 forms the intake ports 170 and 172 and the exhaust port portions 174 and 176 of the cylinder head casting shown in Figure 6. In a similar manner the exhaust port core 90 forms the

exhaust ports

178, 180 and 182 in the cylinder head. The resultant casting may be used as either the left hand or the right hand cylinder head. Except for the fact that dilferent covers are required to seal head openings, the final cylinder head assemblies are similar.

Various modifications in the arrangement and details of the embodiment of the invention described and shown herein will be apparent to those skilled in the art and are contemplated as within the scope of the present invention as defined in the following claims.

I claim:

1. A coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising a water jacket core having a plurality of openings in one side thereof and a plurality of recesses in another side thereof, an exhaust port core having a plurality of generally laterally extending exhaust port-defining arm portions fitting in said openings, and an intake port core having a plurality of generally laterally extending intake port-defining arms fitting in the recesses in the water jacket core.

2. A coring assembly for use in casting a cylinder head of an overhead valve engine, said assembly comprising a water jacket core having a plurality of openings in one side thereof and a plurality of recesses in another side thereof, an exhaust port core having a plurality of generally lateral extensions for forming exhaust ports, said extensions fitting in said openings and being spatially separated from the walls of the water jacket core defining said openings, and an intake port core having a plurality of generally laterally extending intake and exhaust port-defining arms, said arms fitting in the recesses in the water jacket core and being spatially separated from the Walls of said water jacket core defining said recesses, the ends of some of said extensions engaging the ends of some of said arms.

3. A foundry coring arrangement for use in casting a cylinder head of an internal combustion engine, said coring arrangement comprising a water jacket core loose piece adapted to be positioned in a mold and provided with recesses which extend generally laterally relative to the cylinder head to be cast, an intake port core having a plurality of generally laterally extending armsfor forming exhaust ports, said arms extending over said loose piece and through said recesses, said arms being spatially separated from the surfaces of said loose piece, a water jacket core positioned over said arms and said loose piece, said Water jacket core being provided with a plurality of openings in one side thereof, and an exhaust port core having a plurality of generally laterally extending exhaust port-defining arm portions, said arm portions fitting in said openings in the water jacket core and being spatially separated from the walls thereof.

4. A coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising a water jacket core loose piece adapted to be seated on green sand in a drag half of a mold, the upper surface of said loose piece being provided with a recess which extends generally transversely relative to the cylinder head to be cast, a port core having a transversely extending port-defining arm extending over said loose piece and through said recess, an elongated main water jacket core positioned over said exhaust port-defining arm, said main water jacket core being provided with a generally transversely extending opening through one side thereof, and a second port core provided with a port-defining portion having one end thereof extending into said opening through said main water jacket core and contacting the end of said port-defining arm.

5. A mold and coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising a drag half of a mold formed of green sand, an exhaust port water jacket core seated on said ,green sand and provided with recesses in its upper surface, an intake port core positioned on said green sand and having exhaust port-defining arms extending into said recesses, a main water jacket core positioned over the arms of said intake port core and having openings in a side surface thereof, an exhaust port core having portdefining arm portions extending into said openings, and a cope half of a green sand mold position over the drag half and the cores assembled thereon.

6. A foundry mold and coring assembly for use in forming a cylinder head casting for an internal combustion engine, said assembly comprising a drag half of a mold formed of green sand, an exhaust port water jacket core seated on said green sand and provided with recesses in its upper surface extending generally laterally relative to the cylinder head to be formed, an intake port core positioned on said green sand and having generally centrally located exhaust port-defining arms extending into said recesses, a main water jacket core positioned on said green sand and extending over the arms of said intake port core, said main water jacket core being provided with openings in a side surface thereof, an exhaust port core having intake and exhaust port-defining extensions projecting into said openings, the ends of said exhaust port-defining extensions being seated on the ends of the exhaust port-defining arms of said intake port core, and a cope half of a green sand mold positioned over the drag half of the mold and the cores assembled thereon.

7. A method of assembling cores for use in casting a cylinder head of an internal combustion engine which comprises placing an exhaust port Water jacket core having recesses therein in position on green sand in a drag half of a mold, thereafter positioning an intake port core on said green sand with port-defining arms of said intake port core extending over and through the recesses in said exhaust port water jacket core, placing a main Water jacket core over the arms of said intake port core, and subsequently positioning an exhaust port core adjacent one side of said main water jacket core with port-defining extensions of said exhaust port core projecting into openings in said Water jacket core.

8. A method of forming a mold and coring assembly for use in casting a cylinder head of an internal combustion engine, said method comprising placing a water jacket core loose piece in position on green sand in a drag half of a mold, thereafter positioning an intake port core on said green sand with an exhaust port-defining arm of said intake port core extending into a recess in the upper surface of said loose piece, placing a main water jacket core over said arm With core locators on said main Water jacket core engaging core prints in said green sand, subsequently inserting a curved port-defining portion of an exhaust port core into an opening in a side of the main Water jacket core so that the end of said portdefining portion contacts said arm, and thereafter positioning a cope half of a green sand mold over the resultant core assembly and drag half of the mold.

9. A method of casting a cylinder head of an internal combustion engine, said method comprising placing a water jacket core loose piece in position on green sand in a drag half of a mold, thereafter positioning an intake port core on said green sand with a pair of generally laterally extending exhaust port-defining arm portions of said intake port core projecting over and through recesses formed in the upper surface of said water jacket core loose piece and with other portions of said intake port core resting on said green sand, placing a main water jacket core over said arm portions with core locators on said main water jacket core engaging corresponding core prints in said green sand, subsequently inserting curved port-defining arm portions of an exhaust port core into openings in a side of the main water jacket core, whereby the ends of said port-defining arm portions of said exhaust port core engage the ends of the port-defining arm portions of said intake port core, thereafter positioning a cope half of a green sand mold over said drag half and assembled cores, pouring molten metal around said cores into the mold cavity formed between the drag half and cope half of the green sand mold, and permitting said molten metal to solidify.

10. A coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising an elongated water jacket core having a plurality of openings in a side thereof, and a port core having a longitudinally extending supporting bar portion positioned adjacent said side of the water jacket core and a plurality of port-defining arm portions integral with said bar portion projecting generally transversely therefrom, said bar portion being spatially separated from said side of the water jacket core, said arm portions extending into said openings and being spatially separated from the Walls of the water jacket core defining said openings.

11. A mold and coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising drag and cope halves of a green sand mold privided with indentations in the green sand for forming combustion chambers, spark plug pockets and rocker arm pockets, an intake port core positioned on the green sand in the drag half of the mold beneath the cope half of the mold, said intake port core being provided with a plurality of arms for forming intake ports in said cylinder head, a water jacket core positioned between said mold halves and over said arms, said water jacket core having openings in a side surface thereof, and an exhaust port core between said mold halves provided with a plurality of arm portions extending into said openings for forming exhaust ports in said cylinder head.

12. A foundry mold and coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising a drag half of a mold formed of green sand, a port core having a longitudinally extending bar portion and a plurality of port-defining arms projecting laterally from said bar portion, said bar portion being provided with a core locator engaging a core print in said green sand, a Water jacket core positioned on said green sand and extending over the arms of said port core, and a cope half of a green sand mold positioned over the drag half of the mold and the cores assembled thereon, said cope half being seated on the upper surface of said bar portion and the green sand in the cope half of the mold.

13. A foundry mold and coring assembly for use in casting a cylinder head of an internal combustion engine, said assembly comprising a drag half of a mold formed of green sand, an elongated port core seated on said green sand and provided with generally laterally extending portdefining arms, a Water jacket core positioned on said green sand and extending over the arms of said port core, said water jacket core being provided with openings in a side surface thereof, a second port core having port-defining extensions projecting into said openings, the ends of said port-defining extensions contacting the ends of portdefining arms, and a cope half of a green sand mold positioned over the drag half of the mold and the cores assembled thereon.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS 10 7 Huetteman Mar. 27, 1934 Meyer Apr. 30, 1935 FOREIGN PATENTS Germany May 25, 1943