Abstract:
The lost foam method of casting a cylinder liner with water jacket comprises the steps of creating a blank identical to the liner desired, with a drain defined therein, from a heat-dissipated material such as styrofoam, coating the blank with core wash, placing the blank into a casting mold, filling the mold and a chamber defined within the blank with sand, pouring hot metal into the mold, extracting the formed metal liner from the mold, draining sand from within the chamber and plugging the sand drain.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method of casting a cylinder liner with water jacket. More particularly, the method teaches the use of at least one styrofoam blank within a mold, the blank being identical in configuration to the cylinder liner cast with the method and defining a chamber therewithin which, when filled with sand prior to casting, will produce the passageway defining a circumferential water jacket. The method is applicable for use in both vertical and horizontal casting techniques. 
     PRIOR ART 
     Heretofore, various methods of casting a cylinder liner with water jacket have been proposed. Also, casting may be accomplished in either a vertical or horizontal orientation. 
     Typically, such casting methods provide a mold which is multisectional, with the sections being positioned to define an air space between inner and outer mold sections which when filled with molten metal, define the cylinder liner. When it is desired to incorporate a water jacket into the liner, a complex core of solidified sand must be produced which, when suspended within the air space between the inner and outer mold sections, will not be replaced by the molten metal, thus creating a water path between inner and outer surfaces of the liner. 
     To accommodate suspension of such core, which may be of one or more sections, each section includes a plurality of radial arms which extend outwardly of the core and which must engage and be precisely supported by multiple outer sections of the mold for concentricity. This complexity of methodology requires the mold to be complex, of great precision, and therefore time consuming to arrange. It is thus inherently costly. 
     Further, cylinder liners are presently cast one at a time, due to complexity of the methodology used in creation thereof. 
     SUMMARY OF THE INVENTION 
     Accordingly, a primary object of the present invention is to provide a simplified, and less costly, method of casting a cylinder liner with water jacket. 
     This object, as well as others, is accomplished by the method of the present invention wherein at least one foam blank conforming to the shape of the cylinder liner with water jacket is created and positioned within a mold, the blank including a circumferential cylindrical chamber therein and being coated with core wash, the mold and cylindrical chamber being filled with sand prior to introduction of molten metal into the mold, the molten metal replacing the foam blank, with the foam, dissipated by the heat of the metal, escaping from within the mold in the form of gas, with sand in the chamber being drained via a drain after cooling and removal of the casting, to define the water jacket flow path, with the drain being plugged after drainage of sand therethrough. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a cylinder liner with water jacket cast according to the method of the present invention, with internal structures thereof shown in phantom. 
     FIG. 2 is a cross sectional view through a mold containing at least one foam blank used in creating the cylinder liner of FIG.  1 . 
     FIG. 3 is an identical cross sectional view through the foam blank of FIG. 2, showing the foam blank only. 
     FIG. 4 is a further cross sectional view through the foam blank taken at a diameter perpendicular to that of FIG.  3 . 
     FIG. 5 is an enlarged cross sectional view through a sand drain port of the blank and is taken along line  5 — 5  of FIG. 4, and shows a cross section of a plug for the port. 
     FIG. 6 is a top plan view of the blank showing a first embodiment for the drain port and is taken along line  6 — 6  of FIG.  4 . 
     FIG. 7 is a top plan view of the blank showing a second embodiment for the drain port and is taken along line  7 — 7  of FIG.  3 . 
     FIG. 8 shows one top plan view of a sand filled mold with a plurality of blanks therein. 
     FIG. 9 shows another top plan view of a sand filled mold with a plurality of blanks therein. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in greater detail, there is illustrated therein a cylinder liner with water jacket made in accordance with the teachings of the method of the present invention and generally identified by the reference numeral  10  (hereinafter referred to as liner  10 ). 
     As illustrated, the liner  10  includes an inner cylindrical wall  12  (shown in phantom) and an outer cylindrical wall  14 . Between the walls  12  and  14  is defined a chamber  16  which serves as a water passageway, or water jacket,  16  of the liner  10 . An entrance  18  into the water jacket  16  is provided at one suitable position and an exit therefrom (not shown) is provided at another suitable position so that there may be a flow of cooling water through the water jacket  16  and into a cylinder head (not shown) to be engaged thereupon. 
     Further, a plurality of air ports  22  are provided, girdling the liner  10  and extending through the walls  12  and  14  for intake of air by a piston (not shown) reciprocating within the cylinder defined by the inner wall  12 , in known manner. 
     As stated above, creation of the liner  10  has heretofore been a complex, time consuming and expensive task. 
     Thus there has been a need for a simpler method of producing the liner  10  and it is believed the method of the present invention fills that need. 
     Referring now to FIGS. 2-9, there is illustrated therein, in its most simplistic form, the method and structures used in accomplishing the method. 
     Turning first to FIG. 2 for an overview of the simplified method, it will first of all be seen that a blank  24  is created which is an exact duplication of the liner  10  desired to be cast. The blank  24  may be made of any material which is similar to styrofoam in its characteristic of being dissipated by bubbling away at high temperatures. 
     The blank  24 , in a preferred embodiment thereof is made of two sections  26  and  28 , a first section  26  of which defines the inner cylindrical wall  12  of the liner  10  and a second section  28  which defines the outer wall  14  of the liner  10 , with the sections  26  and  28  of the blank  24  being configured to define a longitudinal cylindrical chamber  30  therebetween, with the chamber  30  being intermittently interrupted by the presence of air throughports  32  girdling the blank  24  and extending from outside of the second section  28  through the first section  26  of the blank  24 . 
     Although the preferred embodiment of the blank  24  is defined as being of two section construction, this is not to be construed as limiting. 
     Also, it will be understood that the entrance  18  and exit of the water jacket  16  need not be defined prior to casting, but may be provided by any suitable means such as drilling through an appropriate surface of the cast liner  10  to accommodate any required positioning thereof, as illustrated in FIG. 4, where the second section  28  of the blank  24  is shown to be uninterrupted. 
     Once the sections  26  and  28  are appropriately joined together, they are then coated almost completely, inside and out, with a coating  33  of a compound known as core wash which will not allow molten metal to seep therepast. Only desired points of ingress and egress are not coated. 
     For example, if vertical casting were selected, an upper wall  34  of the blank  24 , which is downwardly disposed for casting in this instance, would remain intermittently uncoated to produce an ingress for the metal in a bottom-up method. 
     One pattern of coating  33  is illustrated in FIG. 3, with the coating  33  being left off the remaining Figures for purposes of clarity. 
     With the method of the present invention wherein the coating  33  encases the blank  24 , a significant benefit is obtained which may not be readily apparent. In this respect, in methods of casting presently utilized, the liner  10  must necessarily undergo a significant amount of machining to have a functionally required configuration because a significant amount of excess metal is inherently present in such casting. 
     Such required machining is significantly reduced if not altogether eliminated by the present method because the blank  24 , in the first instance is identical in configuration to the desired liner  10  to be cast, and, in the second instance, with the coating  33  in place therearound, the metal will not seep past the barrier created by the coating  33 , the coating  33  also acting to reduce friction against which the metal is to flow, and therefore allowing the casting to be as near net size as possible. With the liner  10  being created near net size using the present method, it will be understood that any significant machining requirement is avoided. 
     The coated blank  24  is then inserted into a mold  40  which is of a significantly greater horizontal extent than the blank  24 , creating a void  42  around the blank  24 . 
     Further, as illustrated in the drawings, the blank  24  is inserted in a manner where a drain  44  leading into the chamber  30  faces upwardly. In the embodiment illustrated in FIG. 5, for use in vertical casting, the drain  44  is provided in what would be an underside  46  of the section  28  when righted. 
     It will be understood, however, that the drain  44  may also be provided at a radial point along an upwardly disposed portion of the circumference of the liner  10 , if the liner  10  where to be horizontally cast. 
     Considering the drain  44  in more detail, any suitable configuration thereof for use in filling/draining of the chamber  30  by sand  47  could be used. 
     In this respect, as illustrated in FIG. 6, the drain  44  could be defined as a circular channel  44  leading into the chamber  30 . Such circular channel  44  would be sealed off by engagement of a ring shaped plug  48  therewithin, the plug  48  being fixed to the liner  10  in any suitable manner, such as by welding. A cross section of such plug  48  is shown in FIG.  5 . 
     Alternatively, the drain  44  could be defined as a radial array of spaced apart bores  44  as illustrated in FIG. 7, with each bore  44  being sealed with a plug  48 , a cross section of which is shown in FIG. 5, the plug  48  again being fixed to the liner  10  is any suitable fashion. 
     It will be understood that sealing of the drain  44 , in any workable embodiment thereof, would necessarily take place after the cooled casting of the liner  10  were removed from the mold  40 , righted, and drained of sand  47 . 
     Inasmuch as the blank  24  is necessarily identical to the liner  10  to be created therewith, it will logically follow that ports and channels will be provided in and on the blank  24  which are identical to those desired in the cast liner  10 . 
     It must be understood therefore that not only the exterior surfaces of the blank  24  but any surfaces past which molten metal fed into the ingress must not flow must also necessarily be coated with a coating  33  of core wash so as to remain open. 
     To the contrary end, so that the core wash coating  33  does not interfere with flow of molten metal to necessary areas, it is taught to engage any sections of the blank  24  together prior to dipping in or “coating” with core wash so that the core wash coating  33  does not adhere to the blank  24  at areas defining seams or points of juncture between sections of the blank  24 . 
     Summarizing, the foam blank  24  is created, core washed, and then seated within the mold  40  in a manner placing the drain  44  facing upwardly. Sand  47  is then poured into the mold  40  external and internal to the blank  24 , with the chamber  30  between the sections  26  and  28  of the blank  24  also being filled with sand  47  via the drain  44 . Molten metal is then delivered into the mold  40  in known manner, causing the styrofoam to dissipate from the bottom up through contact with the rising molten metal, which replaces the styrofoam. 
     Once the mold  40  is filled with molten metal, the metal is allowed to cool. After cooling, the formed metal liner  10  is removed from within the sand filled mold  40  and turned right side up, as shown in FIG.  1 . 
     Once the liner  10  is righted, gravity takes over, drawing sand  47  out of the chamber  30  through the now downwardly directed drain  44 . 
     Once the sand  47  is removed, the drain  44  is plugged in the manner described above, producing the cylinder liner with water jacket  10 , the disclosed method being far simplified over previous methods of manufacture. 
     The simplicity of the method provides a further distinct advantage. It allows for a plurality of spaced apart blanks  24  to be received within an extended mold  40 , with a single sprue  50 , used in directing molten metal through the mold  40 , being capable of supplying the metal to the plurality of blanks  24 , as illustrated, in one embodiment, in FIG. 8, and in a further embodiment in FIG.  9 . 
     Of course, it will be understood that the embodiments illustrated are best suited for vertical casting of the liner  10  and again should not be construed as limiting. 
     As described above the method of the present invention provides a number of advantages, some of which have been described above and others of which are inherent in the invention. Also, modifications may be proposed to the method without departing from the teachings herein. Accordingly the scope of the invention should only be limited as necessitated by the accompanying claims.