Abstract:
An exemplary casting assembly for an engine block includes, among other things, an insert and at least one magnet configured to retain the insert in a predefined position within an engine block mold cavity. An exemplary engine block casting method includes, among other things, positioning at least one insert in a mold cavity, retaining the insert in position with at least one magnet, introducing material into the mold cavity to form an engine block, and solidifying the material to secure the insert within the engine block.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates generally to magnetic insert retention in die cast tooling. More particularly, the disclosure relates to magnetic insert retention and position control for over-molded inserts in die cast tooling for an engine block. 
       BACKGROUND 
       [0002]    Die cast components can be configured to incorporate over-molded (cast-in-place) inserts that provide certain attributes that are not attainable in a bulk cast media, or which are not feasible to create in the cast tooling process. The insert can be positioned and retained within the tooling via tooling design features. However, certain types of components provide unique challenges for over-molded inserts. 
         [0003]    One such component is a cast-in-place main journal, also known as a “bulkhead insert,” for a high pressure die cast engine block. The geometry of the insert is such that it cannot be secured within the tooling without the use of opposed die halves. The use of opposing die halves to secure the insert presents the risk of collision between the halves that could potentially damage the tooling or produce a part with a compromised insert that may be difficult to detect in the finished casting operation. 
       SUMMARY 
       [0004]    A casting assembly for an engine block according to an exemplary aspect of the present disclosure includes, among other things, an insert and at least one magnet configured to retain the insert in a predefined position within an engine block mold cavity. 
         [0005]    In a further non-limiting embodiment of the foregoing casting assembly, the insert comprises a bulkhead insert defining an engine crank bore. 
         [0006]    In a further non-limiting embodiment of any of the foregoing casting assemblies, the magnet comprises an electromagnet or permanent magnet. 
         [0007]    In a further non-limiting embodiment of any of the foregoing casting assemblies, an electrical circuit cooperates with the at least one magnet to detect a presence of the insert in the engine block mold cavity. 
         [0008]    In a further non-limiting embodiment of any of the foregoing casting assemblies, the engine block is aluminum and the insert comprises a material other than aluminum. 
         [0009]    In a further non-limiting embodiment of any of the foregoing casting assemblies, the material of the insert comprises a ferrous material. 
         [0010]    In a further non-limiting embodiment of any of the foregoing casting assemblies, a cooling circuit cools the at least one magnet if a temperature of the magnet exceeds a predetermined temperature. 
         [0011]    In a further non-limiting embodiment of any of the foregoing casting assemblies, the engine block mold cavity is provided within a die, and wherein the die includes a bore configured to receive the magnet, and wherein the cooling circuit is at least partially received within the bore. 
         [0012]    In a further non-limiting embodiment of any of the foregoing casting assemblies, there is at least one temperature sensor to determine the temperature of the magnet. 
         [0013]    An engine block casting method according to an exemplary aspect of the present disclosure includes, among other things, positioning at least one insert in a mold cavity, retaining the insert in position with at least one magnet, introducing material into the mold cavity to form an engine block, and solidifying the material to secure the insert within the engine block. 
         [0014]    In a further non-limiting embodiment of the foregoing method, the material comprises aluminum and the insert is comprised of a material other than aluminum. 
         [0015]    In a further non-limiting embodiment of any of the foregoing methods, the material of the insert comprises a ferrous material. 
         [0016]    In a further non-limiting embodiment of any of the foregoing methods, the insert comprises a bulkhead insert defining an engine crank bore. 
         [0017]    In a further non-limiting embodiment of any of the foregoing methods, the method includes detecting a presence of the insert in the mold cavity prior to introducing material into the mold cavity via an electrical circuit that cooperates with the at least one magnet. 
         [0018]    In a further non-limiting embodiment of any of the foregoing methods, the at least one insert comprises at least two inserts and including retaining each insert in position with at least one magnet. 
         [0019]    In a further non-limiting embodiment of any of the foregoing methods, the at least two inserts comprise a first bulkhead insert and a second bulkhead insert that each define an engine crank bore. 
         [0020]    In a further non-limiting embodiment of any of the foregoing methods, the method includes cooling the at least one magnet if a temperature of the magnet exceeds a predetermined temperature. 
         [0021]    In a further non-limiting embodiment of any of the foregoing methods, the magnet comprises an electromagnet or permanent magnet. 
         [0022]    A vehicle component casting method according to an exemplary aspect of the present disclosure includes, among other things, positioning at least one insert in a mold cavity, retaining the insert in position with at least one magnet, cooling the magnet if a temperature of the magnet exceeds a predetermined temperature, and introducing material into the mold cavity to form a vehicle component. 
         [0023]    In a further non-limiting embodiment of any of the foregoing methods, the vehicle component is an engine block. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0024]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
           [0025]      FIG. 1  shows a schematic section view of an example engine block die tooling and bulkhead insert. 
           [0026]      FIG. 2  is a schematic section view of an example engine block with cast-in-place bulkhead insert formed from the tooling shown in  FIG. 1 . 
           [0027]      FIG. 3A  is a schematic section view of a permanent magnet example for position verification in an engine block die. 
           [0028]      FIG. 3B  is an example circuit diagram as used with the permanent magnet configuration of  FIG. 3A . 
           [0029]      FIG. 4A  is a schematic section view of an electromagnet example for position verification in an engine block die. 
           [0030]      FIG. 4B  is an example circuit diagram as used with the electromagnet configuration of  FIG. 4A . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    This disclosure relates generally to an engine block having a main journal. To create the main journal within the engine block, the engine block is cast about an insert that is referred to as bulkhead insert. The engine block is formed within a die that is configured to hold the insert in a desired position within the die such that the insert can be cast-in-place, i.e. over-molded. 
         [0032]      FIG. 1  shows a schematic representation of a crank case die  10  including a bulkhead insert  12  that defines a bulkhead insert bore  14 . The crank case die  10  has a first side that faces a die cavity as indicated at  16  and a second side that faces a die holder as indicated at  18 . The bulkhead insert  12  is located in a first cavity  20  in the die  10  that faces the die cavity  16 . The die  10  also includes a second cavity  22  that receives at least one magnet  24  that is used to retain the insert  12  in a desired position within the first cavity  20 . 
         [0033]    In one example shown in  FIG. 2 , an engine block  30  is cast from an aluminum material and the inset  12  comprises a ferrous material. In this example, the ferrous bulkhead insert  12  is incorporated into the engine block  30  during a casting process that utilizes the at least one magnet  24  to hold the insert  12  in the correct orientation during casting. The magnet  24  provides the ability to locate the insert  12  tightly off of a single die piece  10  and does not require any locating assistance from an opposing die half. 
         [0034]    In the example shown in  FIG. 1  there are two inserts  12  and each insert  12  is retained in the desired position with at least one magnet  24 . It should be understood that while the example shows two inserts  12 , the tooling could be configured to include additional inserts  12 . Further, the magnets  24  could be used to retain other types of inserts that may be needed within the engine block  30 . 
         [0035]    In one example, the magnet  24  comprises a permanent magnet. In another example, the magnet  24  comprise an electromagnet. As known, permanent magnets create their own magnetic field while electromagnets produce magnetic fields only through the application of electricity. When using a permanent magnet, the magnet should provide sufficient magnetic force to retain the insert  12  in the desired position during the casting process. The electromagnet offers the advantages of being about to control the level of the magnetic force as wells as providing on/off control. 
         [0036]    The magnets  24  are positioned within the second cavity  22 , which is aligned with the first cavity  20  that receives the insert  12 . An electronic control unit  32  is associated with the magnets  24  to detect a presence of the insert  12  in the die  10  prior to introducing material into the die cavity  16 . During the casting process, the inserts  12  are placed within the cavity  20  and tightly held in the correct orientation by the magnets  24 . Once the presence of the inserts  12  is detected, material is then poured into the die cavity  16  around the inserts  12  and the casting process takes place in a known manner. 
         [0037]      FIGS. 3A-3B  show an insert positional verification example for a permanent magnet configuration. As shown in  FIG. 3A , the bulkhead insert  12 , which defines the crank journal bore  14 , is received within die  10 . The die  10  includes a first cavity  22   a  for a first permanent magnet  24   a  and a second cavity  22   b  for a second permanent magnet  24   b . The magnets  24   a ,  24   b  are positioned close to, or in direct contact with, the insert  12 . One of the first and second permanent magnets  24   a ,  24   b  is associated with a first line  34   a  in from a voltage supply VS and the other of the first and second permanent magnets  24   a ,  24   b  is associated with a second line  34   b  out to a voltmeter VM. 
         [0038]    An example electrical circuit  36  is shown in  FIG. 3B , which the electronic control unit  32  uses to detect the presence of the insert  12  in the die  10  prior to introducing material into the die cavity  16 . The circuit  36  includes at least one switch S 1  that is used to detect the presence of the insert  12 . An excitation voltage is supplied to the permanent magnets via the voltage supply VS and the voltage is measured via the voltage meter VM to confirm circuit completion. When the bulkhead insert  12  is present in the die  10 , the switch S 1  is closed, the circuit  36  is completed and the presence of the insert  12  is confirmed. When the bulkhead insert  12  is not present in the die  10 , the switch S 1  is open, the circuit  36  is incomplete and the presence of the insert  12  is not confirmed. 
         [0039]      FIGS. 4A-4B  show an insert positional verification example for an electromagnet configuration. As shown in  FIG. 4A , the bulkhead insert  12 , which defines the crank journal bore  14 , is received within die  10 . The die  10  includes a cavity  22  for the electromagnet  24   c . The electromagnet  24   c  is positioned close to, or in direct contact with, the insert  12 . There is a first line  34   a  in to the electromagnet  24   c  from a voltage supply VS and a second line  34   b  from the electromagnet  24   c  out to an ammeter AM. 
         [0040]    An example electrical circuit  38  is shown in  FIG. 4B , which the electronic control unit  32  uses to detect the presence of the insert  12  in the die  10  prior to introducing material into the die cavity  16 . An excitation voltage is supplied to the electromagnet  24   c  via the voltage supply VS and the amperage is measured via the voltage ammeter AM to confirm presence. When the bulkhead insert  12  is present in the die  10  there is an impedance of the magnetic field MF and the presence of the insert  12  is confirmed. When the bulkhead insert  12  is not present in the die  10  there is no impedance of the magnetic field MF and there is confirmation that the insert  12  is not present. 
         [0041]    In one example, the magnet  24  is cooled by a cooling circuit  40  that is housed within the die  10 . The magnet  24  can be cooled if a temperature of the magnet  24  exceeds a predetermined temperature. The predetermined temperature is preferably set at a temperature that would be below a temperature that would degrade the magnetic force capability of the magnet. 
         [0042]    As shown in  FIG. 1 , the cooling circuit  40  is received within the second cavity  22  at a position adjacent to the magnet  24 . A plug  42  seats a spot cooling lance  44  within the cavity  22 . A sensor  46 , such as a thermocouple for example, is used to sense the temperature of the magnet  24 . The plug  42  can be configured to provide a support feature  48  to position the sensor  46  relative to the magnet  24 . The sensor  46  can be configured to communicate with the electronic control unit  32  to monitor the temperature of the magnet  24  and to control the cooling circuit  40 . 
         [0043]    The cooling lance  44  includes an input path  50  that is used to direct a cooling fluid, such as water for example, into the cavity  22  to cool the magnet  24 , and includes an output path  52  that draws heated fluid out of the cavity  22 . It should be understood that while  FIG. 1  shows a cooling circuit  40  for one of the two magnets  24 , the cooling circuit  40  would also be used with additional magnets within the tooling. The cooling circuit  40  can be a dedicated cooling circuit for the magnets, or could be part of a tooling cooling circuit. 
         [0044]    Using the magnets  24  to retain the inserts  12  within a single die  10  offers several advantages over prior tooling configurations. With prior configurations, in order to retain the bulkhead insert within the die, the insert had to be captured by extending a die piece through the cavity steel insert and main journal through hole of the bulkhead insert to lock it into place. This traditional approach is typical for cast-in cylinder liners, steering wheel armature hubs, and other examples where a mandrel or pin can retain the insert in the die draw. The disadvantage with this configuration is that the movement of the retention piece would be out of die draw, which would make die construction more complex and expensive, and would also increase maintenance requirements and costs in operation. Additionally, the position of the insert is critical for function of the engine, and the required clearances to allow proper function of the retaining die piece would not provide tight tolerance on location or position of the insert. Further, the required clearances would provide opportunity for flashing of molten aluminum to jam or lock the die components. 
         [0045]    Using magnets to retain the insert in the correct position provides a configuration where there are no moving parts and no opportunity for flash related complications. Further, the magnets provide the ability to locate the insert tightly off of a single die piece (the same die piece where upper journal halves would be cast in a typical high pressure die cast engine block). Further, the use of a cooling circuit to cool the magnet prevents operating temperatures from exceeding the optimal temperature range of the magnet. 
         [0046]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.